• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.110-115
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• 2001

Today, effective utilization of sophisticated networks greatly influences the activities of a business, making performance evaluations of computer network systems a necessity, We have developed a special computer network simulator capable of automatically generating a model based on data accumulated by a network analyzer to guide the user in selecting ideal parameters. The simulator was developed to provide user-friendly analysis for engineers involved in the actual network design. This paper gives an overview of the simulator and describes an example application of evaluating a network design that anticipates the future increase in traffic for a company introducing voice over frame relay (VoFR) into a wide area network (WAW).

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.7
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• pp.848-854
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• 1999

In this paper, we designed and implemented a precise pulse motor controller chip that generates the pulse needed to control step motor, DC servo and AC servo motors. This chip generates maximum pulse output rate of 5Mpps and has the quasi-S driving capability and speed and moving distance override capability during driving. We designed this chip with VHDL and executed a logic simulation and synthesis using Synopsys tool. The pre-layout simulation and post-layout simulation was executed by Compass tool. This chip was produced with 100 pins, PQFP package by 0.8${\mu}{\textrm}{m}$ gate array process and implemented by completely digital logic. We developed the test hardware board of performance and the CAMC(Computer Aided Motor Controller) Agent softwate to test the performance of the pulse motor controller chip produced. CAMC Agent enables user to set parameters needed to control motor with easy GUI(Graphic User Interface) environment and to display the output response of motor graphically.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.9
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• pp.146-155
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• 1994

In this paper, we desribe a new system, called BEST, that is used to develop a macromodel or behavioral model easily. It automatically calculates the component values of macromodel represented by equations to satisfy the given specification. Also, it gives the way to analyze both the behavioral model and transistor level circuit, and then compare the analysis results of them to check the correspondence under specific temperature and bias condition, and BEST optimizes the component values of macromodel. Other feature is to characterize MOSFET as switch model which consists of PWL-RC network. Finally, it is possible to generage multi-level netlist which consists of macro/switch/transistor level circuits, and user can determine the trade-off between simulation speed and accuracy. With the graphic user interface form of macromodel development system described above. BEST enable designers to make macromodel by themselves and to uas it. We applied BEST to develop the macromodel for the test circuit and got the 18.6 times simulation speed up with preserving the accuracy within 10% compared to the conventional transistor level circuit simulation. Also, applicability of optimization capability was verified.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.4
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• pp.77-85
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• 2009

This paper proposes an efficient system level simulation method for MIMO-OFDM based system in the multi-cell environment. The proposed method analyzes effects of the cell structure, radio channel characteristics and user mobility. The user mobility effect on the system level performance is considered in both channel gain and distance. The receiver SINR calculation procedure is presented in the system which adopts MIMO-OFDM scheme under various system environments. This method can be flexibly extensible to various system environments and provides computationally efficient system level simulation technique which utilizes link level performance analysis. Extensive computer simulations results are presented to obtain the system performance in the various mobile cellular channels using the proposed method. Also this results are analyzed based on the packet error rate for different distances between the base station located in the center of the cell and the mobile user.

• Journal of the Korea Society of Computer and Information
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• v.10 no.4 s.36
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• pp.165-171
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• 2005

High speed computer, large scale storage device and high speed computer network are computing infrastructure which we can easily access to in these days. However, many computer simulations in natural or applied science such as molecular simulation require more computing power as well as larger scale of storage. Grid computing which is a next generation of distributed computing environment, is one of solution for the new requirements. Even though many researches have been going on Grid computing, those are oriented to communication interface and protocols, and middleware like globus tool kits[2, 3]. Therefore research on application level platform or application itself is yet premature and it makes real users be difficult to utilize Grid system for their research. In this paper, we suggest a new user environment and an abstract job model for simulation experiments on MGrid(Molecular Simulation Grid). It will make users be able to utilize Grid resources efficiently and reliably.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.2
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• pp.83-89
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• 2014

An increasing number of children are now using the Internet. They are starting at a younger age, using a variety of devices and spending more time online. It becomes an important problem to protect the children in online environment. The Internet can be a major channel for their education, creativity and self-expression. However, it also carries a spectrum of risks to which children are more vulnerable than adults. In order to solve these problems, we suggested a binding model of user attributes for enhanced user authentication. We also studied the requirements and prerequisites of a binding model of user attributes. In this paper we described the architecture of binding model of user attributes and showed the effectiveness of the suggested model using simulation. This model can be utilized to enhanced user authentication and service authorization.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.931-934
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• 2005

This paper describes an adaptive recommendation system that provides real-time personalized trading advice to the investors based on their profiles and trading information environment. A proposed system integrates Stochastic technical analysis and artificial neural network that incorporates an adaptive user modeling. The user model is constructed and updated based on initial user profile and recorded user interactions with the system. The information presented to each individual user is also tailor-made to fit the user's behavior and preference. A system prototype was implemented in JAVA. Experiments used to evaluate the system's performance were done on both human subjects and synthetic users. The results show our proposed system is able to rapidly learn to provide appropriate advice to different types of users.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.10
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• pp.921-927
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• 2013

This paper presents a user interface for vision based indirect teaching of a robotic manipulator with Kinect and IMU (Inertial Measurement Unit) sensors. The user interface system is designed to control the manipulator more easily in joint space, Cartesian space and tool frame. We use the skeleton data of the user from Kinect and Wrist-mounted IMU sensors to calculate the user's joint angles and wrist movement for robot control. The interface system proposed in this paper allows the user to teach the manipulator without a pre-programming process. This will improve the teaching time of the robot and eventually enable increased productivity. Simulation and experimental results are presented to verify the performance of the robot control and interface system.

• ETRI Journal
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• v.38 no.1
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• pp.30-40
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• 2016

Co-channel interference between macro-femtocell networks is an unresolved problem, due to the frequency reuse phenomenon. To mitigate such interference, a secondary femtocell must acquire channel-state knowledge about a co-channel macrocell user and accordingly condition the maximum transmit power of femtocell user. This paper proposes a pilot-based spectrum sensing (PSS) algorithm for overlaid femtocell networks to sense the presence of a macrocell user over a channel of interest. The PSS algorithm senses the pilot tones in the received signal through the power level and the correlation metric comparisons between the received signal and the local reference pilots. On ensuring the existence of a co-channel macrocell user, the maximum transmit power of the corresponding femtocell user is optimized so as to avoid interference. Time and frequency offsets are carefully handled in our proposal. Simulation results show that the PSS algorithm outperforms existing sensing techniques, even at poor received signal quality. It requires less sensing time and provides better detection probability over existing techniques.

• Journal of the Korea Society of Computer and Information
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• v.24 no.4
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• pp.57-63
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• 2019

In this paper, we propose a new framework to control VR(Virtual reality) contents in real time using user's mouth-wind and acceleration sensor of mobile device. In VR, user interaction technology is important, but various user interface methods is still lacking. Most of the interaction technologies are hand touch screen touch or motion recognition. We propose a new interface technology that can interact with VR contents in real time using user's mouth-wind method with acceleration sensor. The direction of the mouth-wind is determined using the angle and position between the user and the mobile device, and the control position is adjusted using the acceleration sensor of the mobile device. Noise included in the size of the mouth wind is refined using a simple average filter. In order to demonstrate the superiority of the proposed technology, we show the result of interacting with contents in game and simulation in real time by applying control position and mouth-wind external force to the game.