• Journal of Korean Institute of Industrial Engineers
• /
• v.28 no.2
• /
• pp.178-186
• /
• 2002

The objective of this study is to evaluate impact of computer-based man-machine interfaces of Korea Next Generation Reactor (KNGR) on the operator mental workload. Empirical experiments were conducted to measure the operator mental workloads of KNGR and Yong-Gwang Unit 3 and 4, respectively. A comparison analysis based on a NASA TLX revealed that Yong-Gwang Unit 3 and 4 were superior to KNGR in terms of the mental workload. Post-hoc analyses showed that the mental workload of senior reactor operators was significantly higher than those of reactor and turbine operators, regardless of plant types. The implications of the findings were discussed in detail.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.29 no.3 s.234
• /
• pp.409-416
• /
• 2005

We need to develop a on-line thermal performance analysis system for nuclear power plant to determine performance status and heat rate of turbine cycle. We have developed PERUPS(PERformance Upgrade System) to aid the effective performance analysis of turbine cycle. Procedures of performance calculation are improved using several adaptations from standard calculation algorithms based on PTC(Performance Test Code). Robustness in the on-line performance analysis is increased by verification & validation scheme for measured input data. The system also provides useful web interfaces for performance analysis such as graphic heat balance of turbine cycle and components, turbine expansion lines, automatic generation of analysis report. The system was successfully applied for YongGwang nuclear plant unit #3,4.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.9 no.5
• /
• pp.49-58
• /
• 2010

The traffic signal controllers being used in the domestic currently are being manufactured based on the korean national police standard which was developed for controlling the quad-light traffic signal having the red, yellow, left-turn arrow, and green lights. But according to the national policy for the traffic operation, they have to be changed to be able to switch the tri-light signal having red, yellow and green lights. In this study, a new tri-light traffic signal controller was designed and developed by the way improving the Signal Control Unit of the existing quad-light standard traffic controller. The Load Signal Unit(LSU) was improved to output 6 signals which are the two assemblies of three signal indications having the red, yellow, and green lights. To enough traffic signals output to control each directional movements and the various transport modes which are car, bus, bike, and pedestrian etc., the connector bus system was designed to be able to accommodate maximum 96 signals outputs being constructed by 16 LSUs. Flasher device was developed to be able to support maximum 32 red signals. In the software, the communication protocol between traffic control center and the traffic signal controller was improved and new signal map code values were defined for the developed LSU controlling the quad-light traffic signal. A model of the quad-light traffic signal controller developed and was tested three operations, protocol-operation, remote-command and control-mode. The test result operated all of them successfully.

• Korean Journal of Construction Engineering and Management
• /
• v.6 no.1 s.23
• /
• pp.186-194
• /
• 2005

The purpose of this study is to examine the problems of the regulations regarding the modification of subcontact price. It also suggests several measures to improve the regulations related to the subcontact price adjustment which help to reduce unnecessary claims and commercial disputes. The literature research, structure and context analysis on the subcontract regulation and survey are adopted as basic research methods. The primary findings of this study are summarized as the following: (1) A provision outlining necessary procedures that an owner and a contractor should notify a subcontract or the adjustment of contact price needs to be made. (2) A provision allowing procedures that subcontactor could make the alteration of subcontract agreement and adjustment of subcontact price needs to be made. (3) The terminology like a unit cost and the rate of contact price needs to be clearly defined in order to improve the criterions of the subcontact price adjustment. (4) The criterions and additional expenses that the contractors ate responsible far need to be defined.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.08a
• /
• pp.308-309
• /
• 2012

One of the critical issues in the growth of multijunction solar cell is the formation of a highly doped Esaki interband tunnel diode which interconnects unit cells of different energy band gap. Small electrical and optical losses are the requirements of such tunnel diodes [1]. To satisfy these requirements, tens of nanometer thick gallium arsenide (GaAs) can be a proper candidate due to its high carrier concentration in low energy band gap. To obtain highly doped GaAs in molecular beam epitaxy, the temperatures of Si Knudsen cell (K-cell) for n-type GaAs and Be K-cell for p-type GaAs were controlled during GaAs epitaxial growth, and the growth rate is set to 1.75 A/s. As a result, the doping concentration of p-type and n-type GaAs increased up to $4.7{\times}10^{19}cm^{-3}$ and $6.2{\times}10^{18}cm^{-3}$, respectively. However, the obtained n-type doping concentration is not sufficient to form a properly operating tunnel diode which requires a doping concentration close to $1.0{\times}10^{19}cm^{-3}$ [2]. To enhance the n-type doping concentration, n-doped GaAs samples were grown with a lower growth rate ranging from 0.318 to 1.123 A/s at a Si K-cell temperature of $1,180^{\circ}C$. As shown in Fig. 1, the n-type doping concentration was increased to $7.7{\times}10^{18}cm^{-3}$ when the growth rate was decreased to 0.318 A/s. The p-type doping concentration also increased to $4.1{\times}10^{19}cm^{-3}$ with the decrease of growth rate to 0.318 A/s. Additionally, bulk resistance was also decreased in both the grown samples. However, a transmission line measurement performed on the n-type GaAs sample grown at the rate of 0.318 A/s showed an increased specific contact resistance of $6.62{\times}10^{-4}{\Omega}{\cdot}cm^{-2}$. This high value of contact resistance is not suitable for forming contacts and interfaces. The increased resistance is attributed to the excessively incorporated dopant during low growth rate. Further studies need to be carried out to evaluate the effect of excess dopants on the operation of tunnel diode.