• Korean Journal of Construction Engineering and Management
• /
• v.3 no.4 s.12
• /
• pp.139-144
• /
• 2002

Management of today's dynamic projects requires a shift of focus from product to process. The purpose of traditional project controls is to conform performance to plan. The purpose of lean project controls is to make the best possible choices at each point in time during the course of the project, as well as contributing knowledge to the parent organizations so they can learn from project experience. The Lean Construction Institute(LCI) proposed the Last Planner System(LPS) capable of accomplishing that purpose, principally through controlling the quality of planning and of management processes themselves, as distinct from concentrating exclusively on project performance. The case project was a pilot project for the implementation of the Last Planner. Consequently, the coordination of the work on this project was extremely successful. The project had its share of challenges. The coordination did not prevent design problems, or supplier errors, but helped the team deal with the problems effectively while maintaining the work flow. The last planner helped the contractors know: a) who will be doing what and where, b) what each one needs from the others, and c) what are the project priorities. The system itself created a more collaborative environment, because it 'demands' that the subcontractors address these issues.

• Proceedings of the KIEE Conference
• /
• 2006.07d
• /
• pp.1901-1902
• /
• 2006

In recent years, it has been a worldwide trend that many power utilities gave their attention to develop and operate their power plants, substation and distribution systems. Following this trend, KEPCO(Korea Electric Power Corporation) has developed many electric automation systems with various communication networks. It has been natural that the automation systems are just focused on to remote devices when they come to be designed. But, we have to shift the focus to the automation system itself. We have developed the Multi-service Optical Transmission System (M-OTS) for electrical power systems. It can be adopt to not only distribution power field but also the transmission power field. The result strongly shows that the system is potentially beneficial in reliability, speed, and expandability. This paper presents some of initial design efforts and results toward a KEPCO's communication system in distribution areas.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.17 no.1
• /
• pp.94-100
• /
• 2017

Stress drain bias dependent current model is proposed for sub-70-nm p-channel metal-oxide semiconductor field-effect transistors (pMOSFETs) under drain-avalanche-hot-carrier (DAHC-) mechanism. The proposed model describes the both on-current and off-current degradation by using two device parameters: channel length variation (${\Delta}L_{ch}$) and threshold voltage shift (${\Delta}V_{th}$). Also, it is a simple and effective model of predicting reliable circuit operation and standby power consumption.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2008.10a
• /
• pp.1305-1308
• /
• 2008

In this study, we redesigned the reliable integrated on-panel display gate driver that was equipped with dual pull-down as well as controlled discharge-path structure to reduce the high voltage stress effect and realized with TSMC 0.35 um CMOS-based technology before. An improved discharge path and a low noise design are proposed for our new a-Si TFT process implementation. Our novel reliable gate driver design can make each cell of shift register to be insensitive to the coupling noise of that stage.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.18 no.5
• /
• pp.550-557
• /
• 2008

A transmission control cable connects the transmission control arm and the control lever mechanically and transfers control effort exerted by a driver to the transmission. It also transfers vibration generated by the engine to the passenger room through mechanical connection. To understand vibration and noise transfer mechanism and to further find a way to suppress the transmission of vibration effectively, a dependable dynamic vibration model is a necessity. A vibration model for a transmission control cable is developed and a simulation study has been conducted to obtain mode frequencies and a transmittability. The resonance frequencies obtained by an harmonic analysis is compared with the noise level measurement data. The measurement agrees with the simulation result thus ensures the reliability of the model.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.11a
• /
• pp.169-172
• /
• 2000

In this paper, an OMM (On-the-Machine Measuring) system has been developed, which can perform measuring and inspection of sculptured surfaces of die and mold, by use of a scanning-type touch probe mounted into the spindle of a NC machine. The calibration procedures of a scanning prove (SP2-1, Renishaw) and an algorithm for measuring surface points by a ball-nosed stylus have been studied. The system has been developed based on commercial CAM software (Z-Master 2000), and tested through measuring a plastic injection molding-die. Also some experimental results of the calibration and measuring for given surface positions are analyzed to verify its accuracy and reliability.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.6
• /
• pp.946-954
• /
• 2016

Energy industry is undergoing a paradigm shift in customer participation in the smartgrid. Customers traditionally consume electrical power. But nowadays not only do they generate electricity from private distributed generations, they can participate in demand response programs with their negawatt power which means a theoretical unit of power representing an amount of energy saved. Therefore development of decision-making criteria for electric load aggregation becomes a greater consideration as an amount of energy saved from demand response resources increases. This paper proposes load aggregators' decision-making criteria in the industrial sector where it made up the largest portion in demand response portfolio in order to assure reliability performance for demand response resources.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.44-45
• /
• 2008

The zone 3 elements of distance relays play an important role during the propagation of cascaded events. The most challenging problem to mitigate catastrophic failures is to distinguish between actual faults with line flow transfer from other disconnected lines. This paper presents an adaptive protective relaying scheme based on Line Outage Distribution Factor(LODF) and Generation Shift Factor(GSF) to prevent zone 3 tripping during the cascaded events. Internet based secure peer to peer communication is recommended as a communication method of proposed scheme. Several communication issues such as reliability, speed and cyber security are discussed. In order to establish the feasibility of the proposed scheme, computer simulations for a six bus system has been performed.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.12 no.5
• /
• pp.25-31
• /
• 2004

In order to prepare for the large power diesel vehicle, the current trend of advanced nations is to shift from the aluminum alloy piston to the steel piston. In this research, a steel forging piston which replaces the aluminum alloy piston is developed to improve the power performance of the diesel engine. The three dimensional flow and combustion analysis of the target engine is conducted. Using the result of the analysis, the piston is optimized, and a prototype of the articulated steel forging piston is built. The reliability of the piston has been evaluated through durability test using a Hydropuls Test Machine for 300,000 km.

• Journal of the Korea Safety Management & Science
• /
• v.1 no.1
• /
• pp.123-134
• /
• 1999

There are several models for process quality assurance by quality system (ISO 9000), process capability analysis, acceptance control chart and so on. When a high level process capability has been achieved, it takes a long time to monitor the process shift, so it is sometimes necessary to develop a quicker monitoring system. To achieve a quicker quality assurance model for high-reliability process, this paper presents a model for process quality assurance when the fraction nonconforming is very small. We design an acceptance control chart based on variable quality characteristic and time-censored accelerated testing. The distribution of the characteristics is assumed to be normal or lognormal with a location parameter of the distribution that is a linear function of a stress. The design parameters are sample size, control limits and sample proportions allocated to low stress. These paramaters are obtained under minimization of the relative variance of the MLE of location parameter subject to APL and RPL constraints.