• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.12C
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• pp.255-260
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• 2001

This paper describes the design of the Register Controlled DLL(Delay-Locked Loop) that achieves fast locking and low Power consumption using a new locking algorithm. A fashion for a fast locking speed is that controls the two controller in sequence. The up/down signal due to clock skew between a internal and a external clock in phase detector, first adjusts a large phase difference in coarse controller and then adjusts a small phase difference in fine controller. A way for a low power consumption is that only operates one controller at once. Moreover the proposed DLL shows better jitter performance Because using the lock indicator circuit. The proposed DLL circuit is operated from 50MHz to 200MHz by SPICE simulation. The estimated power dissipation is 15mA at 200MHz in 3.3V operation. The locking time is within 7 cycle at all of operating frequency.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.5
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• pp.82-87
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• 2008

This paper presents a new fast locking dual-slope phase-locked loop. The conventional dual-slope phase-locked loop consists of two charge pumps and two phase-frequency detectors. In this paper, the dual-slope phase-locked loop was achieved with a charge pump and a phase-frequency detector as adjusting a current of the charge pump according to the phase difference. The proposed circuit was verified by HSPICE simulation with a $0.35{\mu}m$ CMOS standard process parameter. The phase locking time of the proposed dual-slope phase-locked loop was $2.2{\mu}s$ and that of the single-slope phase-locke loop was $7{\mu}s$.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.9
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• pp.2362-2372
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• 1996

This paper deals with the design and development of an Injection-Locking Coupled Oscillators(ILCO), which functions like phase-shifter in the Active Intergrated Phased Array Antenna(AIPAA). This linear array 2-element ILCO consists of two Injection Locking Hair-pin Resonator Oscillators(ILHRO) and an unilateral amplifier. The first and second elements of the ILCO have same frequency tuning range but locking bandwidths of 11.5MHz and 14MHz respectively. A phase shift of .DELTA..PHI.=158.4.deg.(-78.0.deg. to 80.4.deg.) could be obtained inthe second element of ILCO when the first elementof the ILCO was in the reference locking mode(.DELTA..PHI.=0.deg.). When the ILCO is applied to the AIPAA, the predicted beam scanning angle value will be 38.4.deg.. Each ILCO gives good frequency stability and lower AM, FM, and PM noise charactheristics in the mutual coupling lockingmode. The ILCO can not only play a part as the phase shifter for the AIPAA but it can also be usedas the power combining device in the mm-wave frequency range and as a part of a T/R MMIC module.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12A
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• pp.1891-1898
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• 1999

Traditional syntax-oriented serializability notions are considered to be not enough to handle in particular various types of transaction in terms of duration of execution. To deal with this situation, altruistic locking has attempted to reduce delay effect associated with lock release moment by use of the idea of donation. An improved form of altruism has also been deployed in extended altruistic locking in a way that scope of data to be early released is enlarged to include even data initially not intended to be donated. In this paper, we first of all investigated limitations inherent in both altruistic schemes from the perspective of alleviating starvation occasions for transactions in particular of short-lived nature. The idea of two-way donation locking(2DL) has then been experimented to see the effect of more than single donation in distributed database systems. Simulation experiments shows that 2DL outperforms the conventional two-phase locking in terms of the degree of oncurrency and average transaction waiting time.

• Journal of Information Technology Applications and Management
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• v.12 no.4
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• pp.59-70
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• 2005

Flash memories are one of best media to support portable computer's storages in mobile computing environment. The features of non-volatility, low power consumption, and fast access time for read operations are sufficient grounds to support flash memory as major database storage components of portable computers. However, we need to improve traditional transaction management scheme due to the relatively slow characteristics of flash operation as compared to RAM memory. in order to achieve this goal, we devise a new scheme called Flash Two Phase Locking (F2PL) scheme for efficient transaction processing. F2Pl improves transaction performance by allowing multi version reads and efficiently handling slow flash write/erase operation in lock management process. We also propose a simulation model to show the performance of F2PL. Based on the results of the performance evaluation, we conclude that F2PL scheme outperforms the traditional scheme.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.68-69
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• 2002

두 대의 결맞은 레이저는 원자의 고분해 분광이나 광통신 등의 여러 분야에서 응용이 가능하다. 본 연구에서는 세슘 원자분수 주파수표준기와 저속 원자빔 주파수표준기에서 원자의 속도 선택 실험에 사용하기 위한 9.2 GHz의 주파수 차이를 가지는 두 대의 결맞은 레이저를 제작하였다. 결맞은 레이저는 주입 잠금(injection locking)이나 위상 잠금 회로(phase locking loop)를 이용하여 만들 수 있다. (중략)

• The Transactions of the Korea Information Processing Society
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• v.6 no.12
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• pp.3447-3455
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• 1999

Database correctness is guaranteed by standard transaction scheduling schemes like two-phase locking for the context of concurrent execution environment in which short-lived ones are normally mixed with long-lived ones. Traditional syntax-oriented serializability notions are considered to be not enough to handle in particular various types of transaction in terms of duration of execution. To deal with this situation, altruistic locking has attempted to reduce delay effect associated with lock release moment by use of the idea of donation. An improved form of altruism has also been deployed in extended altruistic locking in a way that scope of data to be early released is enlarged to include even data initially not intended to be donated. In this paper, we first of all investigated limitations inherent in both altruistic schemes from the perspective of alleviating starvation occasions for transactions in particular of short-lived nature. The idea of two-way donation locking(2DL) has then been experimented to see the effect of more than single donation in distributed database systems. Simulation experiments shows that 2DL outperforms the conventional two-phase locking in terms of the degree of concurrency and average transaction waiting time under the circumstances that the size of long-transaction is in between 5 and 9.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.191-193
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• 2005

Flash memories are one of best media to support portable computer's storages. However, we need to improve traditional data management scheme due to the relatively slow characteristics of flash operation as compared to RAM memory. In order to achieve this goal, we devise a new scheme called Flash Two Phase Locking (F2PL) scheme for efficient data processing. F2PL improves transaction performance by allowing multi version reads and efficiently handling slow flash write/erase operation in lock management process.

• The KIPS Transactions:PartD
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• v.8D no.1
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• pp.24-31
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• 2001

In this paper, we present an advanced transaction scheduling protocol to improve the degree of concurrency and satisfy the security requirements for multilevel secure database. We adapted two-phase locking protocol, namely traditional syntax-oriented serializability notions, to multilevel secure database. Altruistic locking, as an advanced protocol, has attempted to reduce delay effect associated with lock release moment by use of the idea of donation. An improved form of altruism has also been deployed for extended altruistic locking OffiLl. This is in a way that scope of data to be early released is enlarged to include even data initially not intended to be donated. We also adapted XAL to multilevel secure database and we first of all investigated limitations inherent in both altruistic schemes from the perspective of alleviating starvation occasions for transactions in particular of short-lived nature for multilevel secure database. Our protocol is based on extended altruistic locking for multilevel secure database (XAL/MLS), but a new method, namely two-way donation locking for multilevel secure database (2DL!/-MLS), is additionally used in order to satisfy security requirements and concurrency. The efficiency of the proposed protocol was verified by experimental results.

• Proceedings of the Optical Society of Korea Conference
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• 2004.02a
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• pp.150-151
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• 2004