• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.5A
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• pp.348-357
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• 2012

Recently, smartphone, notebook, PC and other supporting wireless LAN device have come into wide use. By increasing user that use wireless LAN device, wireless traffic also increased. If wireless traffic through one AP is increase, it causes throughput decrease. To solve this problem, wireless LAN service provider install more AP where overload occurred. But this is not enough. Because stations can't know AP's load factor, and APs do nothing for load balancing. In this paper, we propose Multi-Interface Access Point(MIAP) to solve this problem. MIAP operate same as multiple APs with multi-interface, and MIAP measure each interface's load periodically. If MIAP detect overloaded interface, MIAP transfer station from overloaded interface to under-loaded interface. We conducted an experiment for verifying existing problem, and we found this problem occurred. We plan an experiment scenario for a comparison between existing AP and MIAP, and excute these experiment. In the result, we show MIAP with load balancing can improve total throughput about 72% and stabilize delay jitter than existing AP.

• IEIE Transactions on Smart Processing and Computing
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• v.5 no.6
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• pp.440-444
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• 2016

In this paper, an equivalent circuit model for near-field noise emission is proposed to implement a multimedia operation-monitoring system for mobile devices. The proposed model includes a magnetic field probe that captures noise emissions from multimedia components, and a transfer function for near-field noise coupling from a transmission line source to a magnetic field probe. The proposed model was empirically verified with transfer function measurements of near-field noise emissions from 10 kHz to 500 MHz. With the proposed model, a magnetic field probe was optimally designed for noise measurement on a camera module and an audio codec in a mobile device. It was demonstrated that the probe successfully captured the near-field noise emissions, depending on the operating conditions of the multimedia components, with enhanced sensitivity from a conventional reference probe.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.1
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• pp.33-38
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• 2007

In this paper, hardware implementation of interface and control between two robots, the master and the slave robot, are designed. The master robot is the motion capturing device that captures motions of the human operator who wears it. The slave robot is the corresponding humanoid robot arms. Captured motions from the master robot are transferred to the slave robot to follow after the master. All hardware designs such as PID controllers, communications between the master robot, encoder counters, and PWM generators are embedded on a single FPGA chip. Experimental studies are conducted to demonstrate the performance of the FPGA controller design.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.12
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• pp.1851-1857
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• 2016

Existing devices are capable of communicating the OBD information only inside or close to the vehicle without supporting the data transmission to a external server. In this paper, we describe the implementation of IoT device, which can communicate the OBD information to the external server.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.14 no.2
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• pp.164-176
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• 1989

With reference to the Spread Spectrum techniqeu diseussed and further extended by many investigators, the Peseudo-noise Code Polarity Modulation (PNCPM) technique has proposed in this paper. By using this new technique of PNCPM, some problems pertaining to the Spread Spectrum mode has been sloved. In addition by the PNCPM mode it is proposed that data shifting can be easily demodulated every clock(frame) by measn of simple hardware implementaton for the purpose of operating of the asynchroniged detection mode. And in this paper it is shown that PNCPM mode can be easily implemented by the CCD correlator, and is applicable to the Spread Spectrum Multiple Access.

• Journal of Korea Society of Digital Industry and Information Management
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• v.9 no.1
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• pp.79-86
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• 2013

In this paper which it is relating to the DSRC system based road side equipment, we propose the protocol stack architecture of road side equipment and the process structure of the main RM, L7 and LLC layers which is road side equipment device as well. And also we design the signal flow and data-transfer process as well between road side equipment and on board equipment to describe the installation process between road side equipment and von board equipment based on DSRC system. Thus, it is possible to provide various application services between intelligent transportation systems of road side equipment and local server, as well as it enables the local server managing the memorys of on board equipment which entry in service area thru the road side equipment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.275-278
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• 1998

In recent years, miniaturization has become the key factor in the development of mobile communication system. Portable communications and computing devices suffer from two conflicting requirements which are device size to be as small as possible and large, high resolution display. These problems can be solved by virtual display. Any display in which the user views an image through an optical system is a virtual display. It provides a display which is high resolution, appears large to the viewer and at the same time occupies little physical space. In this study, handhold units of mobile communication was investigated through use of the SLA(Scanned Linear Array). The basic SLA mechanism comprises a linear array of LED's, a magnifying lens, and a scan mirror. To optimize virtual image, we investigated optical system design and operating condition for each part.

• Journal of Multimedia Information System
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• v.8 no.1
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• pp.57-60
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• 2021

Industry 4.0 is continuous automation by applying the latest smart technologies to traditional manufacturing industries. It means that large-scale M2M (Machine-to-Machine) communication and IoT (Internet of Things) technologies are well integrated to build efficient production systems by analyzing and diagnosing various issues without human intervention. Edge computing is widely used for M2M services that handle real-time interactions between devices at industrial machinery tool sites. Here, secure data transmission is required while interacting. Thus, this paper focused on a method of creating and maintaining secret key and security tag used for message authentication between end-devices and edge-device.

• Science of Emotion and Sensibility
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• v.22 no.3
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• pp.35-46
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• 2019

Artificial intelligence (AI) technology has been evolving to recognize and learn the languages, voice tones, and facial expressions of users so that they can respond to users' emotions in various contexts. Many AI-based services of particular importance in communications with users provide emotional interaction. However, research on nonverbal interaction as a means of expressing emotion in the AI system is still insufficient. We studied the effect of lighting on users' emotional interaction with an AI device, focusing on color and flickering motion. The AI device used in this study expresses emotions with six colors of light (red, yellow, green, blue, purple, and white) and with a three-level flickering effect (high, middle, and low velocity). We studied the responses of 50 men and women in their 20s and 30s to the emotions expressed by the light colors and flickering effects of the AI device. We found that each light color represented an emotion that was largely similar to the user's emotional image shown in a previous color-sensibility study. The rate of flickering of the lights produced changes in emotional arousal and balance. The change in arousal patterns produced similar intensities of all colors. On the other hand, changes in balance patterns were somewhat related to the emotional image in the previous color-sensibility study, but the colors were different. As AI systems and devices are becoming more diverse, our findings are expected to contribute to designing the users emotional with AI devices through lighting.

• Korean Journal of Optics and Photonics
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• v.17 no.5
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• pp.469-474
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• 2006

A $1{\times}16$ thermo-optic switch with small excess loss using multimode interference(MMI) couplers is designed, fabricated, and measured. This paper introduces the proposed $1{\times}16$ thermo-optic switch, and discusses the measurement results. The $1{\times}16$ thermo-optic switch is farmed as 4-stage which consists of 15 unit devices. The unit devices are the $2{\times}2$ thermo-optic switches with Mach-Zehnder interferometer(MZI) structure. The characteristics of the $1{\times}16$ thermo-optic switch depends strongly on each unit device. The unit deviceconsists of two 3-dB general interference MMI couplers and two single mode waveguide arms as a phase shifter. First of all, the 3-dB optical splitter and $2{\times}2$ MZI thermo-optic switch have been tested to confirm the characteristics of the unit devices of the $1{\times}16$ MZI thermo-optic switch. Using the measurement results of the unit devices, the $1{\times}16$ MZI thermo-optic switch can be produced with better characteristics. The resultant structure of the MMI coupler with the optical light source of wavelength of 1550nm for the $1{\times}16$ thermo-optic switch is that the width and the optimized length are $25{\mu}m\;and\;1580{\mu}m$, respectively. The smallest excess loss fur the unit device is -0.5dB and the average excess loss is -0.7dB.