• Journal of the Korea Institute of Military Science and Technology
• /
• v.16 no.6
• /
• pp.752-761
• /
• 2013

A new gun fire control system has been developed for the Korean next generation frigate class. The engineering requirement was far more tightened than the PKG-A class for the firing range availability and gun control function since 5 inch gun is adopted for the new ship. We mention about the principal technologies required to build a generic gun fire control system and proposed methods for the new gun fire control system. The new system has been designed based on the proposed methods in order to satisfy the requirement and functionality has been proved to be acceptable through the sea trial by Korean navy.

• The Journal of Advanced Prosthodontics
• /
• v.3 no.4
• /
• pp.196-203
• /
• 2011

PURPOSE. This study evaluated marginal fit of glass infiltrated alumina cores fabricated using two techniques and their marginal stability after firing cycles of veneering porcelain. MATERIALS AND METHODS. Fifteen standardized all-ceramic crowns were fabricated on a metal die using each technique: slip cast technique of VITA In-Ceram sprint Alumina (Group A as control) and plastic foil matrix technique of Turkom-Cera fused alumina core system (Group B). Copings were compared between groups and within groups at coping stage and after firing each layer of veneering porcelain. A device was used to standardize seating of copings on the metal die and positioning of the specimens under the microscope after each stage of fabrication. The specimens were not cemented and marginal gap was measured using an image analyzing software (Imagepro Express) on the photographs captured under an optical microscope. Two tailed unpaired 't test' was used to compare marginal gaps in two groups and one way ANOVA was used to analyze marginal distortion within each group at 95% confidence interval. RESULTS. The marginal gap was smaller at the coping stage in group B ($60+30{\mu}M$) than group A ($81+21{\mu}M$) with statistical significance. After firing of veneering porcelain the difference was insignificant. At the final stage, both groups exhibited lower mean marginal gaps than at the initial coping stage with the difference of $11.75{\mu}M$ for group A and $11.94{\mu}M$ for group B, but it was statistically insignificant due to high value of standard deviation. CONCLUSION. Within the limitations of this study, it was concluded that both techniques produced copings with comparable and acceptable marginal fit and marginal stability on firing veneering porcelain.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.65 no.2
• /
• pp.88-93
• /
• 2016

Soft starters are used with large induction motors in blowers, fans, pumps and the crane hoist drives. AC voltage controllers are used as soft starters in induction motors for starting and to adjust its speed. Soft-starter starting system uses phase control method of input electric source through the setting of the thyristor(SCR) firing angle ${\alpha}$, and it can control input electric source stably and continuously from beginning of starting to ending of starting. In this paper, it is verified that power stack of high-voltage with SCR series system possesses dielectric strength and input electric source is controlled stably by phase control. Especially, from the driving experimental of proposed soft-starter operating, a smoothing acceleration and inrush current decrease can be achieved by the series SCR trigger.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2003.10a
• /
• pp.35-38
• /
• 2003

The purpose of this work is to introduce the 1-N grade thruster development program for attitude control of satellites and lunch vehicle systems. Characteristics of the thruster and its performance have been evaluated through hot-firing test of small liquid engine inside a vacuum test cell. Performance evaluation of thruster were made with a variation of propellant injection pressure at steady state and pulse firing mode, respectively. Also hot-fire test system and test procedure are briefly described, too.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.8 no.3
• /
• pp.163-170
• /
• 2000

Accident statistics shows that the portion of fatal occupant injuries due to side impacts is considerably high. The side impact usually leads to a severe intrusion of side structure into the passenger compartment. Furthermore, the safety zone for the side impact is relatively small compared to the front impact. Those kinds of physics for side impact frequently result in a fatal injury for the occupant. Therefore, NHTSA and EEVC are trying to intensify the regulation for the occupant protection against side impact. Both the regulation and recent market trends are asking for an installation of side airbag. There are several types of system configuration for side impact sensing. In this paper, we adopt the acceleration-based remote sensing method for the side airbag control system. We mainly focus on the development of hardware and crash discrimination algorithm of remote sensing unit. The crash discrimination algorithm needs fast decision of airbag firing especially for high-speed side impact such as FMVSS 214 and EEVC tests. It is also required to distinguish between low-speed fire and no-fire events. The algorithm should have a sufficient safety margin against any misuse situation such as hammer blow, door slam, etc. This paper introduces several firing criteria such as acceleration. velocity and energy criteria that use physical value proportional to crash severity. We have made a simulation program by using Matlab/Simulink to implement the proposed algorithm. We have conducted an algorithm calibration by using real crash data for 2,500cc vehicle. The crash performance obtained by the simulation was verified through a pulse injection method. It turned out that the results satisfied the system requirements well.

• 제어로봇시스템학회:학술대회논문집
• /
• 1993.10a
• /
• pp.504-509
• /
• 1993

A heavy load driving system for the gun laying control is designed with the analysis of performance in pointing accuracy and speed. To eliminate the firing noise and high frequency system noise, a .PI. filter is implemented in conjunction with the PI velocity control. To incorporate the gunner's commands in the PID position control loop easily, a .mu.-processor is utilized in the position control loop. Main difficulties in the heavy load driving system exist in the design of motor drivers and heat sinkers. With an appropriate design of the motor drivers and heat sinkers, the performance of the gun laying system is analyzed by the simulation.

• Proceedings of the KIEE Conference
• /
• 1994.07a
• /
• pp.202-204
• /
• 1994

This paper is describing a voltage control of variable speed synchronous generator for wind-per generation system. The exciting system is adopted that the generator operates in a variable frequency and constant voltage. The generating voltage is controlled by field current varying the firing angle controller.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.6 no.4
• /
• pp.22-28
• /
• 2003

In the conventional weapon system, such as gun and small arms, it Is a general trend that for maximization of its performance and enhancement of its effectiveness, the firing control system(FCS) is developed and applied with the guns and small arms in the world. The FCS of the small arms for infantry man is composed of a few of sensors for acquisition of input data of FCS, such as range measurement, position sensing of weapon, temperature, etc., computer, displayer and power pack, and also the air burst munition is developed in parallel for the maximization of FCS's effectiveness. Since the flight time setting fuze for the air burst munition is adapted for next me, the measuring device of the muzzle velocity is needed to overcome the variation of muzzle velocity due to producing procedures and the differences of the using temperatures and so maintain the burst position accuracy This paper contained the technical information on the development of the measuring device of muzzle velocity, which designed in compact & light weight configuration with reliability and accuracy.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.99-103
• /
• 2017

As a development test of the 75-tonf LOx/Kerosene liquid rocket engine for KSLV-II first Stage Engine, hot firing test of 75-tonf engine are performed. The current status of development test on first stage 75-tonf engine system including combustion chamber, turbopump, gas generator, propellant supply system are presented. During the 75tonf engine test campaign, the development of startup sequence of LOx-Kerosene engine system, engine startup using pyrostarter, ignition of gas generator, steady operation and engine shutdown is successfully performed. As a passenger test during engine hot firing tests, Thrust Vector Control system (TVC) of the engine are also evaluated during engine hot firing test. The results of hot firing test of 75-tonf thrust engine system will be used for the design confirmation and performance evaluation of 75 tonf engine system for KSLV-II first Stage.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.10 no.4
• /
• pp.397-402
• /
• 2005

A new control algorithm of soft starter is proposed for the reduction of the inrush current during the grid connection of the induction-type wind power generator. Currently, the fixed speed wind turbine using induction generator is the most popular wind generation system in Korea. It is shown that the amount of inrush current mainly depends on the control algorithm of the soft starter, a thyristor-based grid connection device. For the simulation study, a 600kw wind turbine simulation model is developed and the transient waveforms are investigated with conventional md proposed methods. Also experimental results using 3.7kW experimental set-up show that the peak value of inrush current is reduced about 20$\%$ using proposed algorithm.