• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.229-232
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• 2000

This research aims at developing a low-cost PC-NC system based on one-CPU and investigating the feasibility of its application to a simple-function lathe. Its hardware consists a two axes motion control board including a 24bit counter, 8253 timer, a 12bit DA converter, DIO board for PLC operation and a PC with Intel Pentium 466MHz. The fundamental real-time MC functions such as G-code interpretation, interpolation, position and velocity control of axes are performed. User programming interface with functions of icon manipulation, tool-path simulation and NC-code generation was implemented. In order to achieve real-time control and safety, axis control, NC interpretation, interpolation and user communication are completely executed during every interrupt interval of I msec.

• Journal of the Korea Society for Simulation
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• v.8 no.2
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• pp.45-56
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• 1999

It is necessary that we should control the traffic to not only efficiently use the rich bandwidth of ATM network but also satisfy the users various requirements for service quality. However, it is very difficult to decide which control mechanism would be applied in real network because there are various types of ATM traffic and traffic control mechanisms. In this paper, a smart simulator is developed ot analyze the performance of a UPC(Usage Parameter Control) mechanism which is a typical traffic control mechanism. The simulator consists of a user interface that supports a menu-driven input form and a simulation program that is executed with the users input parameters. Especially, the simulator establishes more powerful and flexible simulation environment since it supports a more complex simulation applying various source traffic to several different UPC mechanisms at the same time and allows an arbitrary user-defined traffic in addition to some well-known traffic.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.8
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• pp.1632-1642
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• 1997

In this paper, we studied the effects of the power control imperfection on the system performances of a microcellular DS/CDMA system. The maximum user capacity, defined as the maximum number of users can be serviced simultaneouly, meeting a given voice quality, is first considered. Then the performence degradation due to the control error is analyzed. The frequency selective Raician channel model is used to characterize a microcellular mobile communication environment. The DS/CDMA system under consideration uses BPSK modulation and convolutional coding/Viterbe decoding with soft decision for forward error correction. It is shown that the user capacity falls linearly down with the increase of the power control error(in terms of the standard deviation in dB) and the interference from users outside the third tier cells have a minor effect on the performance. And the performance of DS/CDMA with the imperfect power control model is made to be less than 50% of that with perfect power control moded.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.750-753
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• 2003

In this paper, we have developed the web-based management system for greenhouse teleoperation. The remote control system consists of database, web-server, controller in greenhouse, and clients. The database in the server stores user informations and greenhouse conditions, and is used to manage user login and conditioning data. The management system developed by using Java applet, which is a client program for effective and easy management of greenhouse, monitors the greenhouse in real time. Master and driver boards installed in greenhouse control unit. Database on flowering to collect and analyze data exchanges data with the server. The greenhouse can be managed effectively by timer routine, repeat control within setting time, and algorithm of setting points. Also, the greenhouse conditions can be controlled by manual or remote controller (PC) through web browser in internet. Furthermore, all of the control devices of the greenhouse are managed by remote control using PC and checked via camera installed in greenhouse.

• Journal of Korea Society of Industrial Information Systems
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• v.14 no.4
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• pp.91-100
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• 2009

In this paper, we propose autonomous intelligent wheelchair system which recognize the commands using the gaze recognition and avoid the detected obstacles by sensing the distance through range sensors on the way to driving. The user's commands are recognized by the gaze recognizer which use a centroid of eye pupil and two reflection points extracted using a camera with infrared filter and two infrared LEDs. These are used to control the wheelchair through the user interface. Then wheelchair system detects the obstacles using 10 ultrasonic sensors and assists that it avoid collision with obstacles. The proposed intelligent wheelchair system consists of gaze recognizor, autonomous driving module, sensor control board and motor control board. The gaze recognizer cognize user's commands through user interface, then the wheelchair is controled by the motor control board using recognized commands. Thereafter obstacle information detected by ultrasonic sensors is transferred to the sensor control board, and this transferred to the autonomous driving module. In the autonomous driving module, the obstacles are detected. For generating commands to avoid these obstacles, there are transferred to the motor control board. The experimental results confirmed that the proposed system can improve the efficiency of obstacle avoidance and provide the convenient user interface to user.

• The KIPS Transactions:PartA
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• v.10A no.5
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• pp.487-492
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• 2003

To satisfy the requirements for QoS of Users using multimedia content stream service, it is required to control mechanism for QoS based on class priority, URFA classifies the user by two classes (super class, base class) and controls the admission ratio of user's requests by user's class information. URFA increases the admission ratio class and utilization ratio of stream server resources.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.10
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• pp.4703-4723
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• 2018

In recent years, dense small cell network has been deployed to address the challenge that has resulted from the unprecendented growth of mobile data traffic and users. It has proven to be a cost efficeient solution to offload traffic from macro-cells. Software defined heterogeneous wireless network can decouple the control plane from the data plane. The control signal goes through the macro-cell while the data traffic can be offloaded by small cells. In this paper, we propose a framework for cell virtualization and user association in order to satisfy versatile requirements of multiple tenants. In the proposed framework, we propose an interference graph partioning based virtual-cell association and customized physical-cell association for multi-homed users in a software defined small cell network. The proposed user association scheme includes 3 steps: initialization, virtual-cell association and physical-cell association. Simulation results show that the proposed virtual-cell association outperforms the other schemes. For physical-cell association, the results on resource utilization and user fairness are examined for mobile users and infrastructure providers.

• Smart Media Journal
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• v.8 no.1
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• pp.51-58
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• 2019

This paper describes a gesture application to controlling the special effects of physical devices for 4D contents using the PWM (Pulse Width Modulation) method. The user operation recognized by the infrared sensor is interpreted as a command for 3D content control, several of which manipulate the device that generates the special effect to display the physical stimulus to the user. With the content controlled under the NUI (Natural User Interface) technique, the user can be directly put into an immersion experience, which leads to provision of the higher degree of interest and attention. In order to measure the efficiency of the proposed method, we implemented a PWM-based real-time linear control system that manages the parameters of the motion recognition and animation controller using the infrared sensor and transmits the event.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.6034-6056
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• 2018

This paper describes two user studies in remote collaboration between two users with a video conferencing system where a remote user can draw annotations on the live video of the local user's workspace. In these two studies, the local user had the control of the view when sharing the first-person view, but our interfaces provided instant control of the shared view to the remote users. The first study investigates methods for assisting drawing annotations. The auto-freeze method, a novel solution for drawing annotations, is compared to a prior solution (manual freeze method) and a baseline (non-freeze) condition. Results show that both local and remote users preferred the auto-freeze method, which is easy to use and allows users to quickly draw annotations. The manual-freeze method supported precise drawing, but was less preferred because of the need for manual input. The second study explores visual notification for better local user awareness. We propose two designs: the red-box and both-freeze notifications, and compare these to the baseline, no notification condition. Users preferred the less obtrusive red-box notification that improved awareness of when annotations were made by remote users, and had a significantly lower level of interruption compared to the both-freeze condition.

• Journal of Korea Game Society
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• v.12 no.5
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• pp.23-34
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• 2012

Computer games should keep user's immersion for fun. Flow can be occured on the balance of user's game skill level and the difficulty level of the challenges by an immersion theory. Computer games can make automatic control of the challenge difficulty level but user's game skill makes difficult to know instantly its level on gameplay because the skill is decided by game goals, user tendency, or user experience. In this paper, we proposed a method of measurement of user's gameplay skill level that we can know the skill level instantly on gameplay. The proposed methods require to be implemented in the stages of the design and implementation of the computer game to be used. Computer games can keep continuously the balance of user's game skill level and the difficulty level of the challenges in order to occur flow immersion by using the proposed measurement method and automatic control methods of the difficulty of game challenges.