• Journal of Korea Multimedia Society
• /
• v.21 no.6
• /
• pp.698-704
• /
• 2018

When the new ammunition is designed, it is necessary to confirm in advance how long the target distance is depends on the shape and weight of the designed ammunition. Therefore we can use commercial software such as PRODAS to predict the target distance in the design stage. This commercial software has aerodynamic data for various ammunition shape and calculates the target range by calculating the kinetic equations of the ammunition using the aerodynamic data most similar to the designed ammunition. The ammunition for predicting the target distance through software such as PRODAS is a non-guided ammunition that has no control after launch but the glide type ammunition is guided and control ammunition. So it is predicts the state of ammunition after the launch. A new type of simulator is needed to analyze the maximum range and to verify the onboard guided and control algorithm. The simulator constructed in this paper is an optimized simulator for glide type ammunition. Unlike unmanned aircraft and guided missiles. The rotation characteristics of the ammunition are considered and the navigation initialization algorithm is applied. The constructed simulator confirmed the performance by performing maximum range analysis of glide type ammunition.

• Journal of Korea Society of Industrial Information Systems
• /
• v.11 no.1
• /
• pp.69-76
• /
• 2006

Telematics, which is a compound word of a telecommunication and informatics, provides drivers with useful driving information such as driving path guidance, accident or robbery detection, traffic conditions and other valuable data at real time. This paper proposes and implements how to build a telematics terminal equipped with CDMA and GPS running embedded Linux, to check a vehicle's state through communication between telematics server and vehicle terminals using a cellular phone and to control a vehicle using SMS as shown in Figure 1. In order to do this, we use the SK-VM platform which is mobile terminal platform based on JAVA to design, implement and evaluate it.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.23 no.5
• /
• pp.305-312
• /
• 2018

DC distribution systems has recently taken the spotlight. Concerns over human safety and stability facility are raised in DC distribution systems. Std. IEC 60479 provides basic guidance on "the effects of shock current on human beings and livestock" for use in the establishment of electrical safety requirements and suggests an electrical impedance of the human body. This study analyzes impedance spectrums based on the electrical equivalent impedance circuit for the human body; human body impedances measured by experiments are analyzed below the fundamental frequency (60 Hz). The analysis shows that the equivalent impedance circuit for the human body should be modified at least in low-frequency range below the fundamental frequency (60 Hz). The DC residual current detection method that can classify electric shock accidents of humans and electric leakages of facilities is proposed by applying the analysis result. The detection method is verified by experiments on livestock.

• International Journal of Aeronautical and Space Sciences
• /
• v.16 no.2
• /
• pp.148-156
• /
• 2015

A continuous type side jet controller which has four nozzles with thrust control devices was considered. It is deployed to a missile for high maneuverability and fast controllability in the terminal guidance phase. However, it causes more complex aerodynamic jet interactions between the side jet and the supersonic free stream than does the conventional impulse type side jet with a small single thruster. In this paper, a numerical investigation of the jet interference effects for the missile equipped with a continuous type side jet thruster is presented. A three-dimensional flow field was simulated by using a commercial unstructured-based CFD solver. The numerical simulation method was validated through comparison with wind tunnel test results for the single jet. The method of defining jet direction for this type of side jet control to minimize simulation cases was also introduced. Flow fields investigation and jet interaction effects for various flow conditions, jet pressure ratios and defined jet direction conditions were performed. From the numerical simulation for the continuous type side jet, extensive aerodynamic interference data were obtained to construct an aerodynamic coefficients database for precise missile control.

• Structural Engineering and Mechanics
• /
• v.47 no.2
• /
• pp.149-166
• /
• 2013

Flexible behaviors in new aerospace structures can lead to a degradation of their control and guidance system and undesired performance. The objectives of the current work are to analyze the vibration resulting from the propulsion force on a Single Stage to Orbit (SSTO) launch vehicle (LV). This is modeled as a follower force on a free-free Euler-Bernoulli beam consisting of two concentrated masses at the two free ends. Once the effects on the oscillation of the actuators are studied, a solution to reduce these oscillations will also be developed. To pursue this goal, the stability of the beam model is studied using Ritz method. It is determined that the transverse and rotary inertia of the concentrated masses cause a change in the critical follower force. A new dynamic model and an adaptive control system for an SSTO LV have been developed that allow the aerospace structure to run on its maximum bearable propulsion force with the optimum effects on the oscillation of its actuators. Simulation results show that such a control model provides an effective way to reduce the undesirable oscillations of the actuators.

• Journal of the Korean Society for Precision Engineering
• /
• v.28 no.11
• /
• pp.1323-1329
• /
• 2011

The purpose of study was to analyze how the visual information affects balance control of individuals during single leg stance. A total of 27 young normal people (20 males and 7 females, age: $13.7{\pm}2.6$, height: $162.3{\pm}13.2$ cm, weight: $53.9{\pm}13.9$ kg) was voluntarily involved in the experiment. The subjects were requested to maintain balance for 20 seconds with eyes both open and closed on a force plate and then foot ground reaction data were collected for that duration. Results showed that mean velocity of COP in closed eyes condition was larger 1.84 times than that of the open-eyes condition and range of vertical angle was increased approximately one degree in the closed eyes condition. To accomplish a balance, the frequency power in mediolateral and anteroposterior components of the foot-ground reaction force was increased by 1.3~1.4 times. Consequently, visual absence during single leg stance can result in critical loss of balance and lead to instability of body control.

• Journal of the Korean Society of Industry Convergence
• /
• v.18 no.2
• /
• pp.99-109
• /
• 2015

This study proposes a new approach to analyze the impedance and the elasticity of a serial chain of spring-damper system, areal-time collision-free trajectory generation algorithm is proposed. The reference points on a trajectory connected by the spring-damper system have a mechanism for self-position adjustment to solve a collision problem by the impedance, and the local adjustment of each reference point is propagated through the elasticity to a real robot at the end of the spring-damper system. As a result, the overall trajectory consisting of the reference points becomes free of collision with environmental obstacles and efficient having the shortest distance as possible. In this process,, the reference points connected by the spring-damper system take role of virtual robot as global guidance for a real robot, and a cooperative is carried out by the system of robots. A control technology is proposed to implement for mobile robot.

• Journal of Korean Neurosurgical Society
• /
• v.45 no.3
• /
• pp.151-156
• /
• 2009

Objective : It is well known that changes in cerebral hemodynamics occur after traumatic brain injury (TBI). Osmo-regulation in the brain is important for maintaining a constant milieu in the central nervous system. Nevertheless, to our knowledge, early osmolarity changes after minor head injury have not been studied until now. Methods : In this study, serum osmolarity was measured in 99 patients with minor head trauma. As a control group, blood samples were drawn from 99 patients who had a minor trauma in an extremity. Serum osmolarity was estimated using a fully automatic biochemical autoanalyzer within the first 3 hours after the trauma. Results : The mean serum osmolarity levels were $286.08{\pm}10.1\;mOsm/L$ in the study group and $290.94{\pm}5.65\;mOsm/L$ in the control group (p<0.001). However, after age adjustment between the study and control groups, this statistical significance was found to be valid only for patients over 30 years of age. Conclusion : It was noted that serum osmolarity levels decrease in the first 3 hours following minor head trauma in patients over 30 years of age. Further studies into this area could provide guidance for the management/treatment of elderly patients.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.67 no.2
• /
• pp.314-324
• /
• 2018

This paper proposes a linear distributed target tracking filter for multiple unmanned aerial vehicles(UAVs) sharing their passive sensor measurements through communication channels. Different from the conventional nonlinear filtering schemes, the distributed passive target tracking problem is newly formulated within the framework of a linear robust state estimation theory incorporated with a linear uncertain measurement equation including the coordinate transform uncertainty. To effectively cope with the performance degradation due to the coordinate transform uncertainty, a linear consistent robust Kalman filter(CRKF) theory is devised and applied for designing a distributed passive target tracking filter. Through the simulations for typical UAV surveillance mission, the superior performance of the proposed method over the existing schemes of distributed passive target tracking are demonstrated.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.39 no.2
• /
• pp.114-120
• /
• 2011

This paper presents a cooperative standoff tracking of a moving target using multiple unmanned aircraft. To provide guidance commands, vector fields are designed utilizing the Lyapunov stability theory. A roll angle command is generated to keep a constant distance from the target in a circular motion. A speed command and a heading angle command are designed to keep a constant phase angle with respect to the front aircraft and to prevent a collision between aircraft. Numerical simulation is performed to verify the tracking and collision performance of the proposed control laws.