• 전자공학회논문지 IE
• /
• v.45 no.2
• /
• pp.13-19
• /
• 2008

The main advantage of the TLM analysis method is the ease with which even the most complicated transmission line structures. In this paper, using symmetrical condensed node(SCN), the TLM numerical technique has been successfully a lied to microstrip meander line. A detailed technique of the symmetrical condensed node(SCN) may be used to model planar microstrip transmission line is presented. Also, the S-parameters $S_{11}$ and $S_{21}$ of two types of microstrip meander line have been computed. From obtained results, TLM analysis is shown to be an efficient method for modeling complicated structure of planar microstrip transmission line. The TLM results presented here are useful in the design of microwave integrated circuits at higher frequencies region.

• Journal of the Korea Society for Simulation
• /
• v.17 no.3
• /
• pp.45-51
• /
• 2008

The enemy will attempt to destroy our troop's core facilities using various fire supports at the beginning of war. Among these fire supports, artillery is given a most deal of weight and mine artillery is a great threat to our troops because it has a superior predominance on the ability of survival. A study about hitting mine artillery has been developed inside the military field only. However, these studies had been mostly qualitative analyses, thus having limitations in the aspects of nonobjectiveness and simplicity. Current study attempts to develop theory on hitting mine artillery beginning from mine opening until the target got hit, based on the assumption that one side which has inferior force will attack first. We studied on hitting mine artillery in a quantitative way using DEVS method.

• Proceedings of the Korean Society for Language and Information Conference
• /
• 2007.11a
• /
• pp.405-414
• /
• 2007

This paper describes a preliminary work on prosody modeling aspect of a text-to-speech system for Thai. Specifically, the model is designed to predict symbolic markers from text (i.e., prosodic phrase boundaries, accent, and intonation boundaries), and then using these markers to generate pitch, intensity, and durational patterns for the synthesis module of the system. In this paper, a novel method for annotating the prosodic structure of Thai sentences based on dependency representation of syntax is presented. The goal of the annotation process is to predict from text the rhythm of the input sentence when spoken according to its intended meaning. The encoding of the prosodic structure is established by minimizing speech disrhythmy while maintaining the congruency with syntax. That is, each word in the sentence is assigned a prosodic feature called strength dynamic which is based on the dependency representation of syntax. The strength dynamics assigned are then used to obtain rhythmic groupings in terms of a phonological unit called foot. Finally, the foot structure is used to predict the durational pattern of the input sentence. The aforementioned process has been tested on a set of ambiguous sentences, which represents various structural ambiguities involving five types of compounds in Thai.

• International Journal of Aeronautical and Space Sciences
• /
• v.12 no.3
• /
• pp.274-282
• /
• 2011

This paper is focused on dynamic modeling and control system design as well as vision based collision avoidance for multi-rotor unmanned aerial vehicles (UAVs). Multi-rotor UAVs are defined as rotary-winged UAVs with multiple rotors. These multi-rotor UAVs can be utilized in various military situations such as surveillance and reconnaissance. They can also be used for obtaining visual information from steep terrains or disaster sites. In this paper, a quad-rotor model is introduced as well as its control system, which is designed based on a proportional-integral-derivative controller and vision-based collision avoidance control system. Additionally, in order for a UAV to navigate safely in areas such as buildings and offices with a number of obstacles, there must be a collision avoidance algorithm installed in the UAV's hardware, which should include the detection of obstacles, avoidance maneuvering, etc. In this paper, the optical flow method, one of the vision-based collision avoidance techniques, is introduced, and multi-rotor UAV's collision avoidance simulations are described in various virtual environments in order to demonstrate its avoidance performance.

• International Journal of Aeronautical and Space Sciences
• /
• v.12 no.3
• /
• pp.252-259
• /
• 2011

This paper is focused on dynamic modeling and control system design as well as vision based collision avoidance for multi-rotor unmanned aerial vehicles (UAVs). Multi-rotor UAVs are defined as rotary-winged UAVs with multiple rotors. These multi-rotor UAVs can be utilized in various military situations such as surveillance and reconnaissance. They can also be used for obtaining visual information from steep terrains or disaster sites. In this paper, a quad-rotor model is introduced as well as its control system, which is designed based on a proportional-integral-derivative controller and vision-based collision avoidance control system. Additionally, in order for a UAV to navigate safely in areas such as buildings and offices with a number of obstacles, there must be a collision avoidance algorithm installed in the UAV's hardware, which should include the detection of obstacles, avoidance maneuvering, etc. In this paper, the optical flow method, one of the vision-based collision avoidance techniques, is introduced, and multi-rotor UAV's collision avoidance simulations are described in various virtual environments in order to demonstrate its avoidance performance.

• Journal of the Korea Society for Simulation
• /
• v.24 no.4
• /
• pp.51-58
• /
• 2015

Since SBA is regarded as mandatory for DM&S, many M&S frameworks and solutions were developed and applied to military simulation systems. Simulation systems developed based on such framework or solution are consist of simulation control part, scenario generation part and modeling part in common. Although the functions of these parts are similar between another simulation systems, these are developed separately by different implementation, so it causes increase of development cost. In order to solve these problems, we developed a simulation scenario framework which can be reusable regardless of simulation purpose. In this paper, we propose an architecture of simulation scenario framework and its functions.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.13 no.2
• /
• pp.83-91
• /
• 2018

With the development of IT (Information Technology) technology, embedded system and network technology are combined and used in various environments such as military environment as well as everyday life. In this paper, we propose a new airdropped distributed mobility model (ADMM) modeling the dispersion falling of the direct shot of a cluster bomb, and we compare and analyze some representative MANET routing protocols in ADMM in ns-3 simulator. As a result of the analysis, we show OLSR routing protocol is promising in ADMM environment in the view points of packet delivery ratio (PDR), end to end delay, and jitter. In addition, we propose a new adaptation scheme for OLSR, AND-OLSR (Average Node Distance based adaptive-OLSR) to improve the original OLSR in ADMM environment. The new protocol calculates the average node distance, adapts the period of the control message based on the average node distance increasing rate. Through the simulation study, we show that the proposed AND-OLSR outperforms the original OLSR in PDR and control message overhead.

• Korean Journal of Computational Design and Engineering
• /
• v.18 no.3
• /
• pp.189-199
• /
• 2013

The need for reusing synthetic environment data that are employed in the field of modeling and simulation has recently been rising. SEDRIS (Synthetic Environment Data Representation & Interchange Specification) is a standard to exchange synthetic environment data, and is the specification utilized in various military simulations of the Pentagon for representing and exchanging 3D data. SEDRIS represents environmental areas based on a data model; it can represent wind speed, wind directions, weather changes, the information of buildings, as well as terrain data. In some situations, however, the synthetic environment data stored in SEDRIS format should be converted to various visualization formats. First, because SEDRIS is a form of a super-set, it is necessary to verify whether large scale SEDRIS files are stored successfully through visualization. Second, the synthetic environment data should be visualized in some visualization programs for the simulation results to provide an immersive and realistic sense. In this study, we have developed converters for converting SEDRIS data to various visualization formats and visualized the converted results.

• Composites Research
• /
• v.28 no.4
• /
• pp.204-211
• /
• 2015

This paper presents a theory related to a two-dimensional linear cross-sectional analysis, recovery relationship and a one-dimensional nonlinear beam analysis for composite wing structure with initial twist. Using VABS including a related theory, the design process of the composite rotor blade has been described. Cross-sectional analysis was performed at cutting point including all the details of geometry and material. Stiffness matrix and mass matrix were linked to each section to make 1D beam model. The 3D strain distributions within the structure were recovered based on the global behavior of the 1D beam analysis and visualize numerical results.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.33 no.2
• /
• pp.140-147
• /
• 2010

The defense M&S (Modeling and Simulation) techniques are being used by the ROK Army for developing the efficiency and economics of national defense at operational level. But the problem we have found is the lack of interoperability and reusability in defense M&S. CMMS (Conceptual Model of the Mission Space) method have been used by militaries of some advanced countries for the purpose to solve these problems. Therefore, we have adapted the same approach in this paper as adapted by advanced countries military forces as named it as K-CMMS(Korean-Conceptual Model of the Mission Space). Considering the special ROK factors, we have suggested the framework of K-CMMS. We have tried to search for improving the reusability and interoperability in defense M&S.