• Transactions of the Korean Society of Automotive Engineers
• /
• v.22 no.5
• /
• pp.102-107
• /
• 2014

Because of high oil prices and emission gas problems, many governments tighten regulation of fuel economy and emission gas. For Passenger car, there are many researches for plug-in hybrid electric vehicles and they are being manufactured. On the other hand, there are few researches for plug-in hybrid electric bus that is heavy commercial vehicle. In this study, analysis of fuel economy for series plug-in hybrid electric bus according to engine operation strategy based on simulation is conducted. Forward simulator is developed using Autonomie. Engine operation strategies consist on constant engine operation strategy and engine on/off operation strategy. Considering the engine operation strategy, results of vehicle speed, engine operating points and fuel economy are obtained and analyzed. As a result, engine on/off operation strategy has more advantage than constant engine operation strategy in terms of fuel economy.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2023.07a
• /
• pp.505-506
• /
• 2023

본 논문은 임베디드시스템을 적용한 대용량 고부하 레이다 플랫폼의 구동 제어 방안을 제안한다. 군사적 방어 목적용 지대공 유도 미사일 시스템의 구성품인 다기능 레이다 시스템은 고중량의 안테나를 구동해야하는 대용량 고부하 레이다 구동 플랫폼이 필수이다. 이 다기능 레이다 시스템은 360도 방위각 전방향을 일정한 속도로 방위각 회전하며 감시정찰 및 방어 임무를 수행한다. 여기서 대부하 레이다 구동 플랫폼은 방위각회전 구동장치를 이용하여 일정한 속도로 360도 방위각 방향으로 안정적인 회전을 가능하도록 구동 제어한다. 본 구동 제어를 실시간으로 구현하기 위해 임베디드시스템인 DSP(Digital Signal Processor)가 포함된 제어모듈은 구동모듈에 회전구동 명령을 인가하여 일정한 회전각속도로 구동하도록 회전구동 모터를 실시간 제어한다. 고부하 레이다 플랫폼은 직구동모터타입의 회전구동모터, 회전체에 신호와 전원을 공급하기 위한 회전슬립링, 회전체의 회전각도를 측정하기 위한 회전센서로 구성된 방위각회전구동장치와 전체 전원을 공급받아 사용 목적에 맞게 변환하여 공급하는 전원모듈, 구동모터에 구동전원을 공급하기 위한 구동모듈, 회전구동 명령에 따라 구동제어하기 위한 제어모듈로 구성된 제어장치로 구분된다. 본 논문에서는 대부하 레이다 구동 플랫폼을 시뮬레이션 모델링으로 구현하고 제안하는 구동 제어 방안은 구동제어시뮬레이션으로 검증한다.

• Korean Journal of Optics and Photonics
• /
• v.25 no.4
• /
• pp.200-206
• /
• 2014

In this paper, using the value theoretically calculated to emit multidirectionally a beam coming into an optical fiber with diameter of $125{\mu}m$, we modeled and produced a cone-shaped structure at the distal end of the fiber. A numerical simulation was performed for an optical fiber tip in which all incident beams were totally reflected and emitted toward the side, as well as for an optical fiber tip from which the beams could be emitted forward and sideways simultaneously. We produced multidirectional-firing optical fiber tips based on the simulation result and model. Laser fabrication of the optical fiber was done by processing a cone-shaped structure at the distal end of an optical fiber with diameter of $125{\mu}m$ using a femtosecond pulsed laser and polishing the processed surface with a $CO_2$ laser. We also conducted an analysis to compare experimental and simulation results.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.38 no.6
• /
• pp.564-569
• /
• 2010

VOR/DME is the short range radio navigation system for much of the world. The navigation with VOR/DME is used for a long time because of its reliability. It can be used for almost all civil aircraft. To simulate the small aircraft's autopilot system based on VOR/DME system, we developed a simulator by using SIMULINK. The output panel of the simulator was developed according to the cockpit instrument of an actual aircraft. To verify the performance of the simulator several scenarios were planned. And we showed that the simulator performed well.

• Journal of KIISE:Information Networking
• /
• v.33 no.1
• /
• pp.91-102
• /
• 2006

We analyze the performance of MAC-layer Reed-Solomon error recovery in the cdma2000 1xEV-DO Broadcast and Multicast Services (BCMCSs) environment, with respect to the size of the ECB (Error Control Block) and the air-channel condition, and establish the relationship between ECB size, error recovery capacity and service latency. From this we propose an adaptive error recovery scheme which adjusts the size of the ECB to reflect the environment of the mobile nodes so as to meet the required service quality (target bit error-rate), while reducing the latency of real-time applications. Extensive simulation results show the effectiveness of our approach compared to the current static scheme. Proposed adaptive schemes achieves near optimal solution with respect to service latency while satisfying the required service quality.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.21 no.6
• /
• pp.92-99
• /
• 2013

High oil price and global warming problem are being continued all over the world. For this reason, fuel economy and emission of greenhouse gas are regulated by law in many countries. Therefore many companies are researching and producing hybrid electric vehicles (HEVs) which substitute conventional internal combustion engine vehicle. However, these researches and productions are restricted to mainly passenger cars. Because of cost and physical problems, commercial vehicles are difficult to evaluate fuel economy. So simulations are important and it is necessary to know how sensitive parameters that enter into simulation affect. In this paper, forward simulations using AVL Cruise were conducted for analysis of fuel economy for parallel hybrid bus and were repeated by changing each parameter. Based on these results, root mean square errors (RMSE) are calculated for analysis of fuel economy sensitivity. The number of target parameters are 15. These parameters were classified with high and low sensitivity parameter relatively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.26 no.3
• /
• pp.300-304
• /
• 2015

This paper presents an omnidirectionally beam-steerable orthogonal loop resonator for wireless power transfer. The resonator is composed of two orthogonal loops. These connections of two loops and the current direction on the loops are determined by the control of switch. The magnetic field direction is determined by the vector sum of each loop current. The beam is steerable to eight directions by four switch modes. Using the suitable switch mode, the simulation and measurement efficiencies in the whole azimuthal direction are 56.3~60.0 %(deviation 3.7 %) and 41.2~48.7 %(deviation 7.5 %), respectively. The results show a little variation of transmission efficiency in the azimuthal direction.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.21 no.6
• /
• pp.40-48
• /
• 2013

Recently, many types of electric vehicles including a heavy duty vehicle have been developed and released because of the better fuel economy and less gas products. In this study, research about an electric bus which utilizes the wheel motor drive system was conducted. The wheel motor is a motor connected to the wheel directly only with a simple gear so that the developer can utilize the space efficiently and the whole system efficiency will be better because of simple structure. However, because it is different from former types of vehicles which use the differential gear, the development of the integrated control logic is required in order to meet the vehicle stability and driving performance. The developed control logic is composed with direct yaw moment control, regenerative braking control and slip control logics. It is compared to the control logics which does not consist of direct yaw moment control and slip control when the vehicle is exposed in tough situations. For the unification of the control logic, a few maps were developed and applied to determine the output torque of each motor according to the driving status. As a result, it is shown that the developed control logic is more safe and well follow the target speed than the other control logic applied simulations.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.21 no.5
• /
• pp.921-928
• /
• 2017

Unlike wired networks, broadcasting in wireless networks can transmit data to several nodes at a time in a single transmission. The omnidirectional broadcasting of node in wireless networks simultaneously reaches all neighboring nodes. In this paper, we propose a greedy algorithm to solve the minimum power broadcasting problem that minimizes the total transmission power when broadcasting in wireless networks. The proposed algorithm uses a neighborhood list which is a set of nodes that can transmit messages within the maximum transmission range of each node, and among the transmitting nodes that have received the data, the node having the largest number of the neighboring nodes firstly transmits the data to neighboring node. The performance of the proposed algorithm was evaluated by computer simulation, and was compared with existing algorithms in terms of total transmission power and broadcasting frequency for broadcasting to all nodes. Experiment results show that the proposed algorithm outperforms the conventional algorithms.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.44 no.4 s.316
• /
• pp.36-44
• /
• 2007

In this paper, we implement the speech & face recognition system to support various ubiquitous sensor network application services such as switch control, authentication, etc. using wireless audio and image interface. The proposed system is consist of the H/W with audio and image sensor and S/W such as speech recognition algorithm using psychoacoustic model, face recognition algorithm using PCA (Principal Components Analysis) and LDPC (Low Density Parity Check). The proposed speech and face recognition systems are inserted in a HOST PC to use the sensor energy effectively. And improve the accuracy of speech and face recognition, we implement a FEC (Forward Error Correction) system Also, we optimized the simulation coefficient and test environment to effectively remove the wireless channel noises and correcting wireless channel errors. As a result, when the distance that between audio sensor and the source of voice is less then 1.5m FAR and FRR are 0.126% and 7.5% respectively. The face recognition algorithm step is limited 2 times, GAR and FAR are 98.5% and 0.036%.