• The Korean Journal of Archival Studies
• /
• no.16
• /
• pp.3-37
• /
• 2007

The new environment for records managements requires the revolutionary transition from paper-record management to electric-record management. Capturing contents, contexts, and structure informations of the electric records to preserve the evidentiality, authenticity, and reliability is the outstanding issue. The recordkeeping metadata has been placed at the center of the current issue. This study focused on the establishment of the structures of recordkeeping metadata for current and semi-current stages in the life cycle of records. The reason concentrated on current and semi-current stages is that the authenticity of the record is concerned as the evidence of the business processes. Current and semi-current stages are where the records is able to be produced, captured and managed in the business context. The metadata can be collected and preserved with authenticity. This study explained the relations between entities concerned with producing records and proposed the metadata elements by establishing data model.

• Proceedings of the KIEE Conference
• /
• summer
• /
• pp.1239-1241
• /
• 2004

In this paper, electronic ballast with Interleaved Boost Cell is presented. The proposed topology is based on a single-stage ballast which combines a boost converter and a half-bridge series resonant inverter High power factor and low THD(reduction of current ripple) are achieved by using the boost semi-stage operating in discontinuous conduction mode, and inverter semi-stage operated above resonant frequency to provide zero voltage switching is employed to ballast the fluorescent lamp. The experimental results from the ballast system with fluorescent lamps have demonstrated the feasibility of the proposed electronic ballast.

• Proceedings of the KIPE Conference
• /
• 1999.07a
• /
• pp.319-322
• /
• 1999

This paper presents a novel single-stage Power Factor Corrected(PFC) AC/DC forward converter with semi-automatic current shaping in order to achieve the unity power factor and an isolated output. Since the proposed circuit is combined a boost converter used for PFCs with a forward converter used for DC to DC conversion, the over-all size of system could be reduced. And thanks to the zero voltage switching(ZVS) in both switches, the voltage stress can be reduced considerably. A simple auxiliary circuit adopted into the secondary of transformer is composed of lossless components for reducing surge voltage. A prototype which has tow IGBT(Insulated Gate Bypolar Transistor) modules as switching device is manufactured to evaluate the proposed topology. The characteristics of the proposed circuit are tested, and the validity is verified by experimental results.

• Proceedings of the KIEE Conference
• /
• 1997.11a
• /
• pp.456-458
• /
• 1997

The phase-lock technique is applied to a three-phase semi-bridge type battery charger system. Using an inner fast dynamic loop, the phase-locked voltage control (PLVC) technique of three-phase semi-bridge converter is proposed to give a frequency synchronism and to reduce the subharmonics due to the unbalance of transformer or power line. To protect the power devices, the two stage soft-start, function with softly locking the phase and softly increasing the current is presented. As limiting the reference voltage of the inner voltage control loop, muti-lock phenomena are removed on the PLVC loop. A current limit function is also proposed to limit the current of battery and converter. The proposed controller is confirmed through experiment results.

• Journal of the Korean Society for Library and Information Science
• /
• v.37 no.2
• /
• pp.187-205
• /
• 2003

The purpose of this study is to seek the characteristics of Jaryokwan m Korea and suggest the direction of the development for the future, through the analysis of the work process for Record Center(Jaryokwan) regulated in the Law of Records and Archives Management(the Law). According tn the Law, Jaryokwan is supposed to cover the areas of the management of semi-current records, government publications, books, and other records. The analysis of the Law shows that Korean Jaryokwan has the characteristics of divisional management of the semi-current records of governments, pursuing the integrated records and archives management systems, tightening the control function from the current-records stage, emphasizing the protection of evidences and security, contribution to the decentralizing storage of archives and simplifying the access to semi-current records for promoting it's usage. For the future development of Jaryokwan in Korea, this study suggests the imminent needs of the development of ideal model for Korean Jaryokwan, the legal enforcement of posting an Archivist the more detailed regulation, procedures and methods of work, the close collaboration with Library and Information Science, the pursuit of developing as a regional information center, increasing the flexibility of establishing Jaryokwan.

• Proceedings of the KIPE Conference
• /
• 2018.11a
• /
• pp.59-61
• /
• 2018

본 논문에서는 입력전류를 센싱 받지 않아도 역률 보상을 하는 새로운 단일단 브리지리스 AC-DC컨버터를 제안한다. 제안하는 컨버터의 스위치는 전구간에서 ZVS(Zero Voltage Switching) 턴 온을 성취하며, 다이오드는 전구간에서 ZCS(Zero Current Switching) 턴 오프를 성취한다. 제안하는 컨버터의 넓은 범위의 출력전압 제어와 간단한 전력 제어를 위해 SDAB(Semi-Dual Active Bridge)기반의 모듈레이션 기법을 적용하였다. 1kW급 50kHz의 스위칭 주파수를 갖는 시작품을 통해 본 논문의 타당성을 검증하였다.

• Journal of Power Electronics
• /
• v.13 no.4
• /
• pp.592-599
• /
• 2013

This paper investigates a new isolated single-phase AC-DC converter, which integrates a modified AC-DC buck-boost converter with a DC-DC forward converter. The front semi-stage is operated in discontinuous conduction mode (DCM) to achieve an almost unity power factor and a low total harmonic distortion of the input current. The rear semi-stage is used for step-down voltage conversion and electrical isolation. The front semi-stage uses a coupled inductor with the same winding-turn in the primary and secondary sides, which is charged in series during the switch-on period and is discharged in parallel during the switch-off period. The discharging time can be shortened. In other words, the duty ratio can be extended. This semi-stage can be operated in a larger duty-ratio range than the conventional AC-DC buck-boost converter for DCM operation. Therefore, the proposed converter is suitable for universal input voltage (90~264 $V_{rms}$) and a wide output-power range. Moreover, the voltage stress on the DC-link capacitor is low. Finally, a prototype circuit is implemented to verify the performance of the proposed converter.

• Bulletin of the Society of Naval Architects of Korea
• /
• v.23 no.4
• /
• pp.25-34
• /
• 1986

A two-dimensional linear method has been developed for the motion and the second-order steady force arising from the hydrodynamic coupling between waves and currents in the presence of a body of arbitrary shape. Interaction between the incident wave and current in the absence of the body lies in the realm beyond our interest. A Fredholm integral equation of the second kind is employed in association with the Haskind's potential for a steadily moving source of pulsating strength located in or below the free surface. The numerical calculations at the preliminary stage showed a significant fluctuation of the hydrodynamic forces on the surface-piercing body. The problem is approximately solved by using the asymptotic Green function for $U^2{\rightarrow}0$. The original Green function, however, is applied for the fully submerged body. Numerical calculations are made for a submerged and for a half-immersed circular cylinder and extensively for the mid-ship section of a Lewis-form. Some of the results are compared with other analytical results without any available experimental data. The current has strong influence on roll motion near resonance. When the current opposes the waves, the roll response are generally negligible in the low frequency region. The current has strong influence on roll motion near resonance. When the current opposes the wave, the roll response decreases. When the current and wave come from the same direction, the roll response increases significantly, as the current speed increases. The mean drift forces and moment on the submerged body are more affected by current than those on the semi-immersed circular cylinder or on the ship-like section in the encounter frequency domain.

• The Korean Journal of Archival Studies
• /
• no.6
• /
• pp.41-72
• /
• 2002

Electronic environment affects archival community to a great extent. It redefines virtually every stage of archival management form creation to current and semi-current use, to appraisal, and to preservation of records. Faced with the problems caused by ever increasing electronic records, the community is forced to reconsider traditional concepts, approaches, methodologies, even the basic paradigm embedded in archival theory and practice. The present paper discusses the need to reexamine principles and techniques of archival management in the light of digital environment. It also urges archives and archival institutions, the archival profession, or the archival community at large, to participate in this critical enterprise. Success in this endeavor will, eventually, pave the road toward creating, organizing, providing access to, preserving reliably and authentically electronic records and designing proper system for the societal collective memory in recorded digital information.

• Journal of Ocean Engineering and Technology
• /
• v.15 no.4
• /
• pp.34-45
• /
• 2001

In the persent study, we conducted numerical experiments using a three-dimensional baroclinic equation model and a Lagrangian method for clarifying the hydrodynamics in Osaka Bay under the yearly mean discharge and visualizing the behaviour of particles of different settling velocity discharged from Yodo River and sedimentation pattern on the sea bottom. Particles are transported from the Yodo River to the south direction by the residual circulation of the bay head at the first stage, and after most of suspended solids particles are settled down at any layer and returned in the south-east coastal area through bottom layers by an estuarine circulation. The results show that estuarine circulation plays an important part of suspended solids transportation in the Osaka Bay.