• Korean Journal of Optics and Photonics
• /
• v.27 no.3
• /
• pp.95-100
• /
• 2016

High-power quasi-continuous-wave (qcw) operation in Yb-doped double-clad fiber lasers with near-diffraction-limited quality of the output beam is reported. Based on numerical simulation, we built a simple, all-fiberized Yb fiber laser, and a fiber-based master-oscillator power amplifier (MOPA). Both laser systems have successfully produced qcw output with average power greater than 150 W at 1080 nm and 10 ms pulse duration at 10 Hz repetition rate, corresponding to a peak power greater than 1.5 kW for 205 W of pump power at 976 nm. Laser performance, including beam quality and slope efficiency, was characterized in both configurations. Prospects for power scaling and applications are discussed.

• Journal of the Korean Geotechnical Society
• /
• v.19 no.2
• /
• pp.39-48
• /
• 2003

Previous analytical models for key blocks have been based on the assumption of infinite persistent discontinuities. In this paper, a key block analysis method considering the finite persistence of discontinuities is proposed as a stability evaluation method in tunnel constructions, and then applied to an actual example site. Three-dimensional rock block identification with consideration of the persistence of discontinuities is performed by using discontinuity disk model. The removability and stability analyses of rock blocks formed by the identification method are performed. The identification method can handle convex and concave shape blocks. In order to demonstrate the applicability of this developed numerical method to the stability evaluation in tunnel constructions, the analytical results are examined and compared one another.

• Magazine of the Korea Concrete Institute
• /
• v.10 no.4
• /
• pp.135-143
• /
• 1998

The wheel load distribution width for lane load is not specified in current Korea bridge design code(KD code), not like in current AASHTO and AASHTO LRFD specifications which specity it as twice of wheel load distribution width for wheel load. In this study, the wheel load distribution width in continuous reinforced concrete slab bridge is investigated. The major variables affecting the wheel load distribution of a reinforced concrete continuous slab bridge are the span length, bridge width, existence edge beam and boundary condition. From a series of comprehensive parametric study on each variable, the formula for wheel load distribution in continuous reinforced concrete slab bridge is proposed from the nonlinear regression analysis of finite element analysis results. The proposed formulas can be used efficiently in the accurate design of continuous reinforced concrete slab bridges.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.22 no.8
• /
• pp.1765-1773
• /
• 1997

The communication systems which include PLL may have cycle clip problem because of channel noise. The cycle slip problem occurs the synchronization loss of communication system and it may be fatal to the synchronous stream cipher system. While continuous resynchronization is used to lessen the risk of synchronization it has some problems. In this paper, we propose the method which solve the problems by using continuous resynchronization with the clock recovery technique. If the counted value of real clock pulse in reference duration is not same as that of normal state, we decide the cycle slip has occurred. The damaged clock by cycle slip is compensated by adding or subtracting the clock pulse according to the type of cycle slip. It reduced the time for resynchronization by twenty times. It means that 17.8% of data for transmit is compressed.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2002.02a
• /
• pp.395-400
• /
• 2002

지역농가, 농협 단위로 그 지역에서 생산되는 특산물을 직접 살균 가공할 수 있는 연속살균공정과 장치를 설계할 수 있는 프로그램을 웹프로그래밍 언어의 일종인 JSP와 자바를 이용하여 개발하였다. 식품의 산성도 및 물리적 특성과 미생물의 내열특성 등 공정을 설계하는 데 필요한 전문적인 정보를 데이터베이스로 구축하여 사용자가 식품의 특성에 대해 자세하게 모르더라도 쉽게 식품의 살균공정을 설계할 수 있었다. 연속살균장치를 구성하고 있는 부분은 크게 열교환기와 가열유지관, 펌프이며, 이에 대한 설계를 장치 설계 프로그램에서 하였다. 열교환기, 가열유지관등의 설계는 장치의 생산량 및 가격등을 결정하는 주요 요소이며, 살균장치의 성능을 결정짓는 주요한 인자가 된다. 연속살균공정을 설계하는 데 필요한 인자는 식품의 pH특성, 식품의 종류이며, 입력된 값을 이용하여 데이터베이스 내에서 살균할 미생물의 종류와 미생물의 내열특성을 찾아 살균공정을 계산하게 된다. 프로그램을 통해 살균가능한 온도와 시간을 출력한다. 연속살균장치 설계 프로그램의 입력인자는 식품의 살균온도, 식품의 생산량, 열교환기에 사용할 열매체의 종류이며, 프로그램 내에서 열교환기의 전열계수, 식품을 살균온도가지 가열하는 데 걸리는 시간등이 계산되며, 결과값으로 열교환기의 특성 및 파이프의 구경과 길이, 펌프의 용량, 단열관의 구경과 길이가 출력된다. 살균 장치 중 열교환기의 설계에 사용되는 스테인레스 파이프를 국내에서 사용되는 규격별로 데이터베이스화하였으며, 파이프 제작업체 48개 업체, 펌프 제작업체 54개(국내 15개 업체, 미국 39개 업체), 열교환기 제작업체 13개업체(국내 13개 업체)에 대해서 데이터베이스를 구축하여 프로그램을 사용해 설계된 장치를 사용자가 쉽게 제작할 수 있도록 하였다. 공정설계프로그램을 통해 설계된 공정은 데이터베이스에 저장이 되며 장치설계프로그램에서 쉽게 이전에 설계했던 공정을 이용할 수 있도록 하여 공정 설계와 장치설계를 연계하도록 하였다.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.4
• /
• pp.1976-1981
• /
• 2011

In this study, the optimal sewer layout model(Lee, J.H., 2010)[1] was applied to verify the reduction effect of urban inundation in the optimal sewer networks, which designed by this optimal model, for various artificial rainfall events in urban areas. Then the optimal model was developed by Lee, J.H. to minimize the peak outflow at outlet in sewer network. The applied rainfall events are two types. One is the rainfall event which the double peak occurs between specific time distance continuously. The other is the continuous rainfall event with specific rainfall intensity. As the result, in two applied rainfall types, the peak outflows at outlet were reduced in the optimal sewer networks which designed the optimal sewer layout model of Lee, J.H.. Therefore, the peak outflow is reduced because the inflows at each manhole are distributed in the whole sewer networks, it's not delay of inflows by this optimal model.

• The KIPS Transactions:PartA
• /
• v.16A no.2
• /
• pp.79-88
• /
• 2009

In boundary scan architecture, test stimuli are shifted in one at a time and applied to the on-chip system logic. The test results are captured into the BSR and are examined by subsequent shifting. In this paper, we developed a continuous capture test architecture and test procedure using TPG based on boundary scan is used to performance test. In this architecture, test patterns of TPG are applied to CUT with system clock rate, and response of CUT is continuously captured by CBSR(Continuous Capture Boundary Scan Register) at the same rate and the captured results is shifted to TDO at the same rate. The suggested a continuous capture test architecture and test procedure is simulated by Altera Max+Plus 10.0. The simulation results shows the accurate operation and effectiveness of the proposed test architecture and procedure.

• KSBB Journal
• /
• v.8 no.3
• /
• pp.256-265
• /
• 1993

In this study, it was observed that hydrogen productivity varied with changes of input g1ucose concentration and dilution rate in FBR( Fixed Bed Reactor), and CSTR(Continuous Stirred Tank Reactor). We evaluated and compared reaction rate Parameters and internal external and overall mass transfer resistances of immobilized carrier in both reactors. Apparent $K_m$ decreased with increasing dilution rate in FBR but showed a constant value above $0.4h^{-1}$ of dilution rate in CSTR. The experimental results in FBR showed nearly analogous to those in CSTR, however, the performance of FBR resulted in lower hydrogen productivity and an external effectiveness factor but a higher internal effectiveness factor than in CSTR. The overall effectiveness factor obtained with various input 91ucose concentrations showed similar values in both reactors.

• Journal of the Korean GEO-environmental Society
• /
• v.18 no.9
• /
• pp.5-9
• /
• 2017

On the flow of groundwater, the effect of consecutive column-wall in underground as a hydraulic barrier could be identified by conventional geotechnical methods ((1)visualiy identification of wall mass after underground excavating, (2)uniaxial compressive strength test for core of wall mass in underground, (3)in-situ permeability test in the hole after coring wall mass). However, for the cut off the leakage or infiltration of very high concentrated leachate from the waste landfill or the contaminated groundwater, the waterproof effect of consecutive column-wall in underground should be verified more objectively, by in-situ measuring of pH, temperature and salinity. and by evaluating of their consistency and similarity throughout analyzing the characteristics of basic components and their profiles through the series of chemical experiments. Furthermore, its waterproof effect could be verified additionally throughout deciding the similarity more simply by comparing the general distribution patterns including the difference of high and low peaks from the chromatograms using GC-MS for surrounding groundwater.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.1
• /
• pp.205-214
• /
• 2008

To transfer large amount of packets fast in sensor network, it is necessary that the delay between successive packet transmissions should be minimized as possible. In Sensor network, since the Operating Systems are worked on the event driven, the Timer Event is used to transfer packets successively. However, since the transferring time of packet completely is varies very much, it is very hard to set appropriate interval. If interval is too long, delay also becomes too long but if interval is too short, the fail of transfer request would increase. In this paper, we propose ESTEO which reduces the delay between successive packet transmissions by using SendDone Event which informs that a packet transmission has been completed. In ESTEO, the delay between successive packet transmissions is shortened very much since the transmission of next Packet starts at the time when the transmission of previous packet has completed, irrespective of the transmission time. Therefore ESTEO could provide high packet transmission rate given large amount of packets.