• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2325-2327
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• 2002

포항 가속기연구소(PAL)에서는 포항방사광가속기(PLS)가 가동을 시작한 1994년 이후 현재까지 사용되어 온 기존의 제어 시스템을 새로운 환경인 EPICS(Experimental Physics and Industrial Control System) 시스템으로 개발하고 있다. EPICS 시스템의 구성은 IOC(Input/Ouput Controller) 와 OPI(Operator Interface)의 2-Layer로 구성되며 이는 MIU(Machine Interfaces Unit), SCC(Subsystem Computer Control System) 그리고 HMI(Human Machine Interface)로 이어지는 기존의 3-Layer 단계 중 SCC단계를 줄여 2-Layer로 구성된다. 이들 두 계층간의 통신은 Client(OPI)/Server(IOC) 구조의 Channel Access를 통해서 이루어진다. 개발중인 EPICS 시스템은 Open Architecture 구조로 IOC와 OPI 각 부분에서 개발시에 사용된 운영체제나 Hardware 를 사용하지 않고 다른 운영체제나 Hardware를 사용하더라도 하나의 공통부분 즉, Channel Access만 있으면 이를 통해 서로 다른 Subsystem IOC의 데이터를 Access할 수 있다. 전체 EPICS 제어시스템 중 저장링 운전의 핵심이 되는 BPM(Beam Position Monitoring) 및 MPS(Magnet Power Supply) 시스템은 IOC부분에 MVME5100(Target Machine) 보드와 vxWorks(Operating System)를 이용하고 OPI부분에는 SUN Workstation(Host Machine)와 Solaris(Operating System)을 사용하여 개발하고 있다. 본 논문에서는 IOC 및 OPI의 설치 절차와 설치 방법에 대해 기술하였다.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2504-2506
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• 2000

포항가속기(PLS) 제어시스템은 선형가속기와 저장 링 제어시스템으로 분산 독립형으로 운영되어 왔다. 각각의 제어시스템의 구성상 상이한 H/W, S/W구조로 인하여 통합제어의 실현을 구현하지 못하여, 빔 운영상의 두 곳의 운전 감시업무로 인한 인력소요의 낭비를 초래하였다. 이러한 점을 개선하기 위한 선형가속기 및 저장 링 제어시스템의 제어알고리즘의 장점만 살려, 통합운전에 필수적으로 필요한 제어 분야만 새롭게 설계된 개선된 제어시스템에 적용하였다. 개선된 제어시스템의 구성은 디바이스제어에서 GUI(Graphic User Interface)단계까지의 3단계의 제어구조에서 SCC(Subsystem Computer Control System)를 생략한 디바이스 제어 컴퓨터와 GUI실현을 위한 상위 컴퓨터로 운영되고 있다. 디바이스 제어 컴퓨터는 VMEbus 구조의 OS-9 ver3.03 real-time OS가 적용되어 있으며, 상위는 SUN Workstation 환경에 UNIX 운영체제에 Rtworks가 적용되었다.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1558-1559
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• 2006

펨토세컨드 원적외선 가속장치(Femtosecond Far-infrared Accelerator)에는 5 밴드의 클라이스트론이 사용되고 있으며, 이를 구동시키기 위하여 신뢰성이 높고 컴펙트하며 효율성이 좋은 펄스 모듈레이터가 필요하다. 전통적인 방식의 라인타입 공진충전 펄스 모듈레이터는 직류전원을 만들기 위하여 많은 고전압 소자들을 사용한다. 이러한 소자들로는 SCRs, 3상 트렌스포머, 정류 다이오드, 필터 초크, 필터 커패시터, 충전 인덕터, 충전 다이오드, deQing 회로, de-spiking 초크 둥으로 구성된다. 펨토세컨드 원적외선 가속장치의 펄스 모듈레이터에는 이러한 소자들을 사용하는 대신에 고전압 인버터전원장치를 사용함으로써 신뢰성이 높고 컴펙트하며 효율성이 좋은 펄스 모듈레이터를 제작하였다. 전통적인 방식의 라인타입 공진충전 펄스 모듈레이터는 deQing 회로를 사용해야만 하지만, 펨토세컨드 원적외선 가속장치의 펄스 모듈레이터의 빔 전압의 변동폭은 deQing 회로를 사용하지 않고도 0.5 % 범위안에서 동작하기 때문에 출력이 매우 안정적이다. 고전압 인버터전원장치의 사양은 10 KJ, 50KV, 200mA의 전원장치 4개를 병렬로 사용하여 30 Hz로 운전하고 있다. 본 논문에서는 펨토세컨드 원적외선 가속장치의 펄스 모듈레이터의 디자인개념과 출력전압의 변동폭에 관하여 논의하고자한다.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2239-2241
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• 2003

A new RF control system of Pohang Accelerator Laboratory (PAL) storage ring is a subsystem upgraded PAL control system, which is based upon Experimental Physics and Industrial Control System (EPICS). There are 5 control components, Low Level RF System (LRS), Klystron System, Circulator System, Cavity System, Local Cooling Water System (LCW) at the storage ring of PAL. The new RF control system for the storage ring has been under development for one years, first versions of individual VME (Versa Module Europa) Input/output modules under construction and system integration begun. In this system, VMEbus-based hardware is widely used for front-end controllers (FDS), Input/output controller (IOC). A number of Programmable Logic Controller (PLC) and SUN workstations are also used for Operator Interfaces (OPI) in the control system. This paper describes the development VME I/O module to the new control system and how the design of this new system.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1530-1533
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• 2005

Total 12 units of high power klystron-modulator systems as microwave source is under operation for 2.5-GeV electron linear accelerator in Pohang Light Source(PLS) linac. RF power and beam power of klystron are precisely measured for the effective control of electron beam. A precise measurement and measurement equipment with good response characteristics are required for this. Input power of klystron is calculated from the applied voltage and the current on its cathode. Tiny measurement error severely effects RF output power value of klystron. Therefore, special care is needed to measure precise beam voltage. Capacitive voltage divider(CVD) unit is intended for the measurement of beam voltage of 400 kV generated from the pulsed klystron-modulator system. Main parameter to determine the standard capacitance in the high arm of CVD is dielectric constant of insulation oil. Therefore CVD should be designed to have a minimum capacitance variation due to voltage, frequency and temperature in the measurement range. This paper will discuss the analysis of capacitive voltage divider for a pulsed high-voltage measurement, and the empirical relations between capacitance and oil temperature variation.

• Nuclear Engineering and Technology
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• v.54 no.2
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• pp.437-441
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• 2022

In this study, we developed a neutron time-of-flight (nTOF) measurement system for a 1.7-MV tandem proton accelerator with a target covered with 300-nm-thick lithium (Li) layer. With implementation of beam chopping module after its ion source, the accelerator is configured to operate in pulsed-beam mode with a pulse width <50 ns at 20-kHz repetition rate. This enables the gamma flash-type nTOF measurement system to identify the neutron generated with 3-MeV proton beam energy. The nTOF system consists of a 30" cylindrical NaI(Tl) and four stilbene scintillation detectors. The NaI(Tl) scintillator is placed 50 cm from the Li target to measure the time of beam irradiation on the target, and the stilbene detectors are placed 2 and 2.4 m away to measure nTOF at each location. The nTOF system successfully measured the generated neutron energy at irradiated proton energies of 2.6 and 3.0 MeV with an average energy resolution of 15%.

• Journal of Venture Innovation
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• v.5 no.1
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• pp.1-18
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• 2022

There is growing empirical evidence that passion is an important part of entrepreneurship and influences the intentions, behaviors and performance of entrepreneurs, employees and startups. Passion is especially important in an entrepreneurial context, given the effort and challenge that entrepreneurs starting a startup must overcome. The purpose of this study was to confirm the effect of the passion of startup entrepreneurs participating in the accelerator incubation program and the passion of accelerator entrepreneurs and managers on the entrepreneurial performance of incubator startups. In addition, we tried to confirm whether entrepreneurial self-efficacy plays a mediating role in this influence relationship. The survey was conducted online by startups entrepreneur who completed the accelerator incubation program. A total of 330 questionnaires were used for the analysis. As a result of the empirical analysis, it was confirmed that the passion of startup entrepreneurs and the passion of accelerator entrepreneurs and managers all had a positive (+) effect on the entrepreneurial performance of incubator startups. The influence of passion was found to be high in the order of startup entrepreneurs, accelerator entrepreneurs, and accelerator managers. It was confirmed that entrepreneurial self-efficacy plays a mediating role between the passion of startup entrepreneurs, the passion of accelerator entrepreneurs, and the entrepreneurial performance of incubator startups, respectively. However, no significant mediating role was identified between the passion of accelerator managers and the entrepreneurial performance of incubator startups. This study is significant in empirically confirming for the first time that the passion of accelerator entrepreneurs and managers has a positive effect on the entrepreneurial performance of incubator startups. The passion of accelerator entrepreneurs and managers is playing an important role as a hidden lynchpin in creating the entrepreneurial performance of incubator startups. In particular, since the passion of accelerator entrepreneurs has a great influence on the performance of incubator startups, it is necessary to recognize this fact and carefully examine their passion reputation when startups select accelerators.

• Journal of the Korea Concrete Institute
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• v.17 no.3 s.87
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• pp.427-434
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• 2005

An experimental investigation was carried out in order to verify the compressive strength, flexural strength, equivalent bending strength, rebound rate of shotcrete according to silicate accelerator, aluminate accelerator, cement mineral accelerator respectively and to especially evaluate the performance of shotcrete using cement mineral accelerator for high quality. The test result of compressive strength was showed that all accelerators were satisfied the required test value for each age, for the requirement of having the $75\%$ or higher compressive strength ratio to plain concretes at 28 days, cement mineral accelerator with $87\%$ compressive strength ratio was only satisfied. In flexural strength test, cement mineral accelerator was satisfied the flexural strength requirement in steel fiber reinforced shotcrete for each age. Aluminate type was conformed to the requirement for 28 days, but not at 1 day, silicate type was failed to satisfy standard requirement. Rebound rate was measured between $11{\~}19\%$ and cement mineral accelerator was showed comparatively lower rebound rate. Based on the test results, cement mineral accelerator exhibited excellent strength improvement and lower rebound rate compared to the conventional accelerator, its result is showed the possibility of making high performance shotcrete.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1658_1659
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• 2009

PLS(Pohang Light Source) will begin the PLS-II project that has been funded by the KOREA Government in order to further upgrade the PLS which has operated since 1992. The control system of the PLS-II has distributed control architecture, with two layers of hierarchy; operator interface computer (OIC) layer and machine interface computer (MIC) layer. The OIC layer is based on SUN workstation with UNIX. A number of PC-based consoles allow to remotely operating the machine from the control room. PC-based consoles use the Linux or Windows operation system. Similar consoles in the experimental hall are used to control experiments. The MIC layer is directly interfaced to individual machine devices for low-level data acquisition and control. MIC layer is based on VMEbus standard with vxWorks real-time operating system. Executable application software modules are downloaded from host computers at the system start-up time. The MIC's and host computers are linked through Ethernet network. It should enable the use of hardware and software already developed for specific light source requirements. The core of the EPICS (Experimental Physics and Industrial Control System)[1] has been chosen as the basis for the control system software.

• Journal of Radiation Protection and Research
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• v.41 no.2
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• pp.123-131
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• 2016

Background: With the increase in the number of particle accelerator facilities under either operation or construction, the accurate calculation using Monte Carlo codes become more important in the shielding design and radiation safety evaluation of accelerator facilities. Materials and Methods: The calculations with different physics models were applied in both of cases: using only physics model and using the mix and match method of MCNPX code. The issued conditions were the interactions of 600 MeV proton and $290MeV{\cdot}n^{-1}$ oxygen with a carbon target. Both of cross-section libraries, JENDL High Energy File 2007 (JENDL/HE-2007) and LA150, were tested in this calculation. In the case of oxygen ion interactions, the calculation results using LAQGSM physics model and JENDL/HE-2007 library were compared with D. Satoh's experimental data. Other Monte Carlo calculations using PHITS and FLUKA codes were also carried out for further benchmarking study. Results and Discussion: It was clearly found that the physics models, especially intra-nuclear cascade model, gave a great effect to determine proton-induced secondary neutron spectrum in MCNPX code. The variety of physics models related to heavy ion interactions did not make big difference on the secondary particle productions. Conclusion: The variations of secondary neutron spectra and particle transports depending on various physics models in MCNPX code were studied and the result of this study can be used for the shielding design and radiation safety evaluation.