• Current Industrial and Technological Trends in Aerospace
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• v.6 no.2
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• pp.40-50
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• 2008

Most of satellite program process consists of mission analysis, thermal, structure, electronics design, and operation, etc. Each step has several steps like design phase, development phase, and verification phase, etc. As to do this kind of process, very high costs and much time are required, further high risk is included. So for solving those difficulties, satellite developers have designed and used satellite simulator system. In early stage of satellite development, simulator system was just used for a fragment of development and verification, so it could not give enough advantage on satellite development. In order to get high advantage on satellite development, full system level simulators which can be used for several steps for development and verification are evolved. So This paper introduces the trend of simulation systems for satellite development and verification used by several satellite developers.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.08a
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• pp.167-176
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• 2004

The authors have newly developed the “Port Traffic Management System (PTMS)”. The PTMS provides each ship with the detailed planned routes of all the ships entering/leaving the port. This system also has a function to predict the encounter situations between own ship and other ships in the future. Based on information of the present positions, speeds and planned routes of the own ship and other ships, it is possible to predict when and where the own ship will have dangerous encounters with other ships in the future. The software of PTMS was developed from 2001. Then onboard experiments using small training ships equipped with actual AIS were performed in June 2003. From the results of these onboard experiments, the usefulness of PTMS was clarified. In addition to these onboard experiments, the effectiveness of PTMS was confirmed by comprehensive simulator experiments. In the simulator experiments, captains/pilot maneuvered a training ship/container ship in congested waters using PTMS. [t was assumed that all ships have PTMS and send their planned routes. After the simulator experiments, captains/pilot suggested that it is very beneficial if the optimal route of own ship can be automatically calculated. In response to this suggestion, software to calculate the optimal route of own ship using Dynamic Programming was developed. This software calculates the minimum time route from the present position to the destination keeping the danger of collision against other ships under predetermined level. From the result of calculations for multi-encounter situations, it was confirmed that the developed software can provide safe and time-saving route.

• The Transactions of the Korea Information Processing Society
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• v.4 no.1
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• pp.311-323
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• 1997

This paper presents a fast fault simulation system for detecting stuck-at faults in mixed-level combinational logic circuits with gale level and switch -level primitives. For a practical fault simulator, the types are not restricted to static switch-level and/or gate-level circuits, but include dynamic switch-level circuits. To efficiently handle the multiple signal contention problems at wired logic elements, we propose a six-valued logic system and its logic calculus which are used together with signal strength information. As a basic algorithm for the fault simulation process, a well -known gate-level parallel pattern single fault propagation(PPSFP) technique is extended to switch-level circuits in order to handle pass-transistor circuits and precharged logic circuits as well as static CMOS circuits. Finally, we demonstrate the efficiency of our system through the experimental results for switch-level ISCAS85 benchmark combinational circuits and various industrial mixed-level circuits.

• Journal of Mechanical Science and Technology
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• v.19 no.spc1
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• pp.473-480
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• 2005

A three axes marine satellite antenna has been developed. As a design step, a CAD model for the antenna has been created according to the design requirements. Kinematic analyses are carried out to insure design specification and to check collision detection of the CAD model. Marine satellite antennas experience base motions, and a relevant control system should control the three antenna axis to point to the satellites accurately. A sensor fusion algorithm and a PIDA (Proportional, Integral, Derivative, Acceleration) control algorithm are designed and implemented to control the yaw, level, and cross-level angle of a small size satellite marine antenna. Antenna stabilization control experiments are performed using a test simulator which gives the antenna base motions. Experimental results show small pointing errors, which is less than 0.2 degree for the level, cross-level, and yaw axis.

• Journal of the Korea Society for Simulation
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• v.15 no.1
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• pp.35-42
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• 2006

Sensor network, that is an infrastructure of ubiquitous computing, consists of a number of sensor nodes of which hardware is very small. The network topology and routing scheme of the network should be determined according to its purpose, and its hardware and software may have to be changed as needed from time to time. Thus, the sensor network simulator being capable of verifying its behavior and estimating performance is required for better design. Sensor network simulators currently existing have been developed for specific hardwares or operating systems, so that they can only be used for such systems and do not provide any means to estimate the amount of power consumption and program execution time which are major issues for system design. In this study, we develop the sensor network simulator that can be used to design and verify various sensor networks without regarding to types of applications or operating systems, and also has the capability of predicting the amount of power consumption and program execution time. For this purpose, the simulator is developed by using machine instruction-level discrete-event simulation scheme. As a result, the simulator can be used to analyze program execution timings and related system behaviors in the actual sensor nodes in detail. Instruction traces used as workload for simulations are executable images produced by the cross-compiler for ATmega128L microcontroller.

• Journal of the Korea Society of Computer and Information
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• v.18 no.10
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• pp.109-119
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• 2013

An unmanned ground vehicle(UGV) today plays a significant role in both civilian and military areas. Predominantly these systems are used to replace humans in hazardous situations. To take unmanned ground vehicles systems to the next level and increase their capabilities and the range of missions they are able to perform in the combat field, new technologies are needed in the area of command and control. For this reason, we present war field simulator based on information fusion technology to efficiently control UGV. In this paper, we present the war field simulator which is made of critical components, that is, simulation controller, virtual image viewer, and remote control device to efficiently control UGV in the future combat fields. In our information fusion technology, improved methods of target detection, recognition, and location are proposed. In addition, time reduction method of target detection is also proposed. In the consequence of the operation test, we expect that our war field simulator based on information fusion technology plays an important role in the future military operation significantly.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.9
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• pp.3-11
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• 2016

Vehicle to Everything (V2X) communication has been growing to enhance traffic safety by employing advanced wireless communication systems. V2X communication is one core solution for governing and advancing future traffic safety and mobility. In this paper, we design the system level simulator (SLS) of Long Term Evolution (LTE)-based V2X and propose the adaptive transmission scheme for vehicle communication. The proposed scheme allocates the resource randomly in time and frequency domain, and transmit the message according to probability of transmission. The performance analysis is based on freeway case in periodic message transmission. Simulation results show that proposed scheme can improve the cumulative distribution function (CDF) of packet reception ratio (PRR) and average PRR.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.10
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• pp.53-66
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• 1994

In this paper, a fuzzy expert system is developed for fault diagnoisis of a drum-type boiler system in fossil power plants. The develped fuzzy espert system is composed of knowledge base, fuzzification module, knowledge base process module, knowledge base management module, inference module, and linguistic approximation module. The main objective of the fuzzy expert system is to check the states of the system including the drum level and detect faults such as the feedwater flow sensor fault, feedwater flow control valve fault, and water wall bube rupture. The fuzzy expert system diagnoses faults using process values, manipulated values, and knowledge base which is built via interviews and questionaries with the experts on the plant operations. Finally, the validity of the developed fuzzy expert system is shown via experiments using the digital simulator for boiler system is Seoul Power Plant Unit 4.

• Journal of the Korean Society of Systems Engineering
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• v.4 no.2
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• pp.27-33
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• 2008

As a part of development of Korean K2 main battle tank, embedded training computer to be operated in the main equipment, which makes it possible to train without a special-purposed training simulator, was adopted for tank combat training. The category of embedded training of Korean K2 main battle tank includes driving training, gunnery training, single tank combat training, platoon level combat training, and command and platoon leaders combat training. For realization unit level tank embedded training system, the virtual reality was utilized for real time image rendering, and network based real time communication system of K2 tank was utilized for sharing status information between tanks. As a result, it is possible to train themselves on their own tank for enhancing the operational skills and harmonized task with members.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.828-834
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• 1989

On-Line optimization of process units has heretofore been restricted to the individual equipment level using linear approximate models. The advent of the low cost, high speed micro-computer coupled with the speed and robustness of an equation based exact simulator is making real-time optimization of entire process units a reality. The resultant implications for a decision system applied to day-to-day operations, point to a significant change in the way process plants will be managed in the future.