• Proceedings of the Korea Information Processing Society Conference
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• 2016.04a
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• pp.980-982
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• 2016

이 논문은 손가방에 탑재 가능한 IoT기반 락킹 시스템으로 SafeBag 시스템을 설계하고 구현한다. 일반적으로 사람들이 자신의 손가방을 잃어버린 경우, 손가방 내부에 있는 가치 있는 물건을 보호하고 특히, 제3자에게 이들 물건을 탈취되는 것을 방지하기 자동으로 손가방이 잠기기를 바란다. 이러한 요구를 이루기 위한 IoT기반 락킹 시스템은 손가방 내부에 작은 크기의 솔레노이드 잠금 장치를 통한 자동 락킹-언락킹 기능과 스마트폰과 연동된 마이크로 컨트롤러를 이용한 제어 기능 등을 가지고 있어야 한다. 이 논문을 통해 설계 구현되는 SafeBag 시스템은 이러한 기능을 탑재함으로써 손가방을 잃어버린 경우 손가방을 자동 락킹함으로써 가방 내부의 물건을 안전하게 보호해 주는 이점을 제공한다.

• Korean Journal of Optics and Photonics
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• v.10 no.3
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• pp.221-225
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• 1999

The positive branch confocal unstable resonator equipped with an intra-cavity beam splitter has been studied experimentally to achieve low beam divergence in the copper vapor laser. Output laser beams of 0.15 mrad divergence was achieved from the laser system with a 10 cm curvature convex mirror (M=30), and laser beams of 0.1 mrad was achieved for a 5 cm curvature convex mirror (M=60). The power density of the far-field beam from the M=60 resonator laser was 130 times higher than the case of the 2 mrad-operation with the plane-parallel resonator. We also observed the self-mode-locking from the unstable resonator laser pulses.

• Journal of Electrical Engineering and information Science
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• v.2 no.5
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• pp.89-99
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• 1997

The application for real-time database systems must satisfy timing constraints. Typically the timing constraints are expressed in the form of deadlines which are represented by priorities to e used by schedulers. In any real-time applications, since the system maintains sensitive information to be shared by multiple users with different levels of security clearance, security is another important requirement. As more advanced database systems are being used in applications that need to support timeliness while managing sensitive information, protocols that satisfy both requirements need to be developed. In this appear, we proposed a new priority-driven secure multiversion locking (PSMVL) protocol for real-time secure database systems. The schedules produced by PSMVL are proven to e one-copy serializable. We have also shown tat the protocol eliminates covert channels and priority inversions. The details of the protocol, including the compatibility matrix and the version selection algorithms are presented. the results of the performance comparisons of our protocol with other protocols are described.

• Journal of KIISE:Software and Applications
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• v.26 no.2
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• pp.223-233
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• 1999

데이터베이스 공유 시스템(Database Sharing System : DSS) 은 고성능의 트랜잭션 처리를 위해 제안된 구조이다. DSS에서 고속의 통신망으로 연결된 노드들은 별도의 메모리와 운영체제, 그리고 DBMS를 가지며, 데이터베이스르 저장하고 있는 디스크는 모든 노드에 의해 공유된다. 빈번한 디스크 액세스를 피하기 위해 각 노드는 자신의 메모리 버퍼에 최근에 액세스한 페이지들을 캐싱한다. 본 논문에서는 레코드와 같은 미세 단위의 로킹을 지원하는 DSS에서 데이터베이스를 정확한 상태로 복구할 수 있는 회복 기법인 DRCP(Database Recovery using Cached Pages)를 제안한다. DRCP는 정상적으로 동작하고 있는 다른 노드에 캐싱된 페이지의 내용을 참조하여 회복 작업을 수행함으로써 디스크 액세스 수와 회복 과정에서 필요한 로그 스캔의 범위를 줄일 수 있고 , 그 결과 데이터베이스를 빨라 복구할 수 있다는 장점을 갖는다.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10a
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• pp.121-123
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• 2001

새롭게 대두되고 있는 홈 네트워크(Home Network) 환경에서 정보가전은 댁내외에서 제공되는 여러가지 데이터 서비스를 제공받는 단말기로서의 역할을 담당하며, 이러한 데이터를 체계적이고 효율적으로 관리하기 위해서 정보가전용 내장형 데이터베이스 시스템의 필요성이 대두되고 있다. 이 시스템은 기존의 파일이나 메모리 기반 데이터베이스 시스템과 같이 동시성 제어를 지원하여야 하지만, 제한된 자원의 효율적인 활용이라는 제약 조건을 가지고 있다. 본고에서는 이러한 조건에 부합하는 정보가전에 탑재될 내장형 데이터베이스 시스템의 요구조건을 정의하고, 이에 부합되는 동시에 제어의 기법으로 제한적 다중 버전을 이용한 2단계 잠금 기법(Multiversion Technique with 2-Phase Locking)을 제시하고, 이 기법이 기존의 잠금 기법 및 다중 버전 기법보다 정보가전에 적합할 수 있음을 각각의 장단점의 분석을 통해 기술하였다.

• Knee surgery & related research
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• v.30 no.4
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• pp.284-292
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• 2018

Purpose: As the number of total knee arthroplasties (TKAs) increases, the incidence of femoral periprosthetic fractures after TKA is also increasing. This review aimed to suggest a new surgically oriented classification system for femoral periprosthetic fractures. Methods: We investigated the classifications, and current treatment trends for femoral periprosthetic fractures after TKA by means of a thorough review of the relevant literature. Results: Numerous studies reported good results of surgical treatment with modern fixatives including locking compression plates and retrograde intramedullary nails. However, few classifications of femoral periprosthetic fractures reflect the recent developments in surgical treatment. Conclusions: We recommend that surgical management be considered the first-line treatment for femoral periprosthetic fractures after TKA. Our new classification will help in deciding the surgical treatment option for femoral periprosthetic fractures after TKA.

• Current Optics and Photonics
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• v.5 no.3
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• pp.289-297
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• 2021

We describe a comb-mode resolving spectroscopic technique by direct time-domain phase correction of unstable interferograms obtained from loosely locked two femtosecond lasers. A low-cost continuous wave laser and conventional repetition rate stabilization method were exploited for locking carrier and envelope phase of interferograms, respectively. We intentionally set the servo control at low bandwidth, resulting in severe interferograms' fluctuation to demonstrate the capability of the proposed correction method. The envelope phase of each interferogram was estimated by a quadratic fit of carrier peaks to correct timing fluctuation of interferograms in the time domain. After envelope phase correction on individual interferograms, we successfully demonstrated 1 Hz linewidth of RF comb-mode over 200 GHz optical spectral-bandwidth with 10-times signal-to-noise ratio (SNR) enhancement compared to the spectrum without correction. Besides, the group delay difference between two femtosecond pulses is successfully estimated through a linear slope of phase information.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.1
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• pp.115-124
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• 2020

We studied smart door lock of triple security system that strengthened the security capability as it is thought that the criminal case by security vulnerability of door lock is serious in modern society. Remote locking/unlocking function, voice recognition function through mobile phone application built on Eclipse App and optical fingerprint recognition function are implemented in the door lock. Finally, it was confirmed that the security of the door lock can be strengthened through evaluation results of the app-based operation test, the voice recognition operation test, and the fingerprint recognition operation test on the experiment-made door lock system.

• The Transactions of the Korea Information Processing Society
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• v.3 no.7
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• pp.1687-1696
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• 1996

Most of the main memory database systems use two-phase locking(2PL)for concurrency control. The 2PL method is preferred over other methods for concurrency control because of its simplicity and common usage. However, conventional concurrency control solution will function poorly when the data are memory resident. In this paper, we propose a new optimistic concurrency control protocol for a main memory database system. In our proposed protocol, transaction conflict information is used in validation phase to improve data conflict resolution decisions. Our experiments show that the proposed protocol performs better than 2PL in terms of throughput for main memory database system enshrinements.

• Korean Institute of Interior Design Journal
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• v.17 no.5
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• pp.61-71
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• 2008

The study alms to seek a plan of applying the digital technology to housing for the elderly. The purpose of the study was to grasp the needs of the aged on 30 types of digital systems in housing. The subjects were 120 persons aged of more than 60 years and lived in Busan. Data were collected by the individual interview. The following results were drawn from this study. First, the needs of the aged on the digital systems categorized as safe and security, control of indoor environment, and housework support were very high and should be provided at first. Second, the necessary types of digital systems which should be provided to the digital home for the elderly were digital systems for heating control, health checking, sensing of fire and gas leak, and house cleaning. Also, the basic types of digital systems were ones for invasion and burglarproof, emergency, air cleaning, automatic facet, door locking, and waste collecting. Third, the Income and usage level of digital equipment of the aged influenced to the floods of the aged on the digital system. Therefore, in addition to the necessary and basic types of digital systems mentioned above, the income and usage level of digital equipment should be considered in planning the digital home for the elderly.