• Magazine of korean Tunnelling and Underground Space Association
• /
• v.22 no.1
• /
• pp.26-35
• /
• 2020

Tunnelling to bypass major landslide areas is considered as a good and long-term environmentally friendly solution to reduce an existing hazard. In Norway, hundreds of kilometres of tunnels have been constructed in areas prone to landslides and snow avalanches. Although tunnelling is considered as an expensive mitigation strategy for bypassing landslides, analysis indicate that in some cases the cost of building a tunnel can be repaid by savings in driving costs (fuel) alone over a period of 5-10 years due to reduced driving distances. The other benefits of constructing tunnels in landslide areas include savings in time and increased safety. The Norwegian Method of Tunnelling (NMT) is considered safe, efficient and cost effective compared to other tunnelling techniques. Some aspects of NMT, which are considered safe and cost efficient, are presented. The application of updated rock support techniques, including reinforced ribs of shotctrete (RRS), which is a key component of the Norwegian Method of Tunnelling (NMT), is highlighted.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.38 no.7
• /
• pp.481-491
• /
• 1989

A compensation strategy for the phase-difference control method, which has been reported as a new driving method of a 2-phase inverter-fed induction motor, is proposed. The phase-difference control method extends the control range of the speed and eliminates the harmonic contents of the output voltage of the 2-phase inverter-fed induction motor. However, the phase-difference angle becomes narrower, motor efficiency deceases more and pulsating torque increases more. As the counterplan for these shortcomings of the phase-difference control method, a hybrid control method which combines the phase-difference control with the voltage control is proposed. The algorithm to realize a hybrid method is presented. As an example, a model composed of 5 regions has been analyzed by computer simulation in terms of motor performance and the results have been compared with experimental results.

• Proceedings of the KIEE Conference
• /
• 1999.07a
• /
• pp.486-488
• /
• 1999

This paper shows the form of the optimal solution and how to minimize energy of train driving control using SA(simulated annealing). In this paper, we consider the case where a train is to be driven by automatic operation mode along a non-constant gradient, curve and with speed limits. Using the combinational optimal technique, SA, we constructed optimal train driving strategy.

• Journal of Digital Convergence
• /
• v.5 no.1
• /
• pp.35-45
• /
• 2007

High tech companies' strategies are divided into four parts, Market Pull, Technology Push, Market-Driven, and Driving Markets. Market Pull strategy means to search market-needs, chances or new industries with technological chance. Technology Push means to create new market by new technology. While Market driven companies follow market changes, Driving Market companies make or change their markets. This study analyzes how companies recognize their market situations based on technology and which business inclination paths are selected for success. And we would like to know there are performance distinctions based on market differentiation strategies.

• Proceedings of the KIEE Conference
• /
• 1995.07a
• /
• pp.344-346
• /
• 1995

In this paper a drive strategy of AC Servo Motor using Fuzzy method was proposed. Since the transfer function of the plant is nonlinear and very complicated, there are difficultly in driving the system with real time. The performance of out method is confirmed by computer simulation and experimental results. The high performance and high accuracy of the driving system. Fuzzy is designed and proposed.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.25 no.6
• /
• pp.938-948
• /
• 2001

In this paper, we present an exoskeletal haptic device named SKK Hand Master. This device is directly driven linkages actuated with small ultrasonic motors. By adopting ultrasonic motors that have advantageous features useful for cybernetic actuators, a compact haptic device containing whole driving packages can be established without additional power transmissions such as tendons. Methods for measuring joint postures and joint torques are developed and a new control strategy called PWM/PS is proposed to overcome intrinsic disadvantages such as hysteresis. Issues regarding design and construction of the device are addressed and several results of experiments for the evaluations of performance are included.

• Journal of Power Electronics
• /
• v.17 no.4
• /
• pp.953-962
• /
• 2017

Momentum flywheels are widely applied for the generation of small and precise torque for the attitude control and inertial stabilization of satellites and space stations. Due to its inherited system nonlinearity, the tracking performance of the flywheel torque/speed in dynamic/plug braking operations is limited when a conventional controller is employed. To take advantage of the well-separated two-time-scale quantities of a flywheel driving system, the singular perturbation technique is adopted to improve the torque tracking performance. In addition, the composite control law, which combines slow- and fast- dynamic portions, is derived for flywheel driving systems. Furthermore, a novel control strategy for plug braking dynamics, which considers couplings between the Buck converter and the three-phase inverter load, is designed with easy implementation. Finally, experimental results are presented to demonstrate the correctness of the analysis and the superiority of the proposed methods.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 2007.11a
• /
• pp.571-575
• /
• 2007

With intensive competition due to the limited growth of the domestic construction market volume and the opening and construction boom of international construction market, construction firms register to grope strategy of enterprise dimension for improvement such as entry extension of domestic construction market order corporate strategy and international construction market. In this research, influence factors of corporate strategy are extracted and their interrelationships are presented in the domain of change of external environment with the internal and external market system, construction enterprise's internal capacity and corporate strategy, government and the internal and external market. The result of this research will be used for quantitative analysis through system dynamics simulation and basic data of model effectiveness verification through actuality domestic construction enterprise's case study, and can be used to basic data of new corporate strategy establishment because construction enterprise forecasts effect hereafter establishing corporate strategy in construction environment that change rapidly.

• Journal of Korea Port Economic Association
• /
• v.20 no.2
• /
• pp.19-33
• /
• 2004

Recognizing that the main container ports' status is gradually inclining, the Japanese government is driving forward the super hub port project. This project has three goals, unifying Japanese ports separating nationally, diminishing the port costs by 30 percents less than the current port costs of their competitors, and cutting down the lead time of processing import-export freight into 24 hours, Singaporean level. The project will work to some extent, if succeeding, but the effect is doubtful if it will be the fundamental solution of Japanese ports' crisis. I wrote this paper since I thought that this Japanese policy would serve as a good reference of Korea, which had two container ports system and its prospect was not good through the fact that the Busan ports' rank of dealing with containers fell down to the fifth in 2003.

• Journal of Information Technology Applications and Management
• /
• v.10 no.3
• /
• pp.23-44
• /
• 2003

It is needed to search the electronic commerce standardization and to analysis its policies to meet the international situations strategically and forecast the technology surroundings for electronic commerce. This study aims at searching the current state of electronic commerce standardization and analyzing policies on electronic commerce by the driving subject, that is, government and private organization, major countries, and standard classifications of electronic commerce technologies such as e-documents, e-catalog, e-payment, and e-process. The government and private organizations get information for the current state and policies for standardization on electronic commerce and put them practical use to make policies and strategy applications.