• Journal of Information Display
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• v.11 no.2
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• pp.76-83
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• 2010

This paper presents the multi-user autostereoscopic 3D display system constructed and operated by the authors using the time-multiplexing approach. This prototype has three main advantages over the previous versions developed by the authors: its hardware was simplified as only one optical array is used to create viewing regions in space, a lenticular multiplexing screen is not necessary as images can be produced sequentially on a fast 120Hz LCD with full resolution, and the holographic projector was replaced with a high-frame-rate digital micromirror device (DMD) projector. The whole system in this prototype consists of four major parts: a 120Hz high-frame-rate DMD projector, a 49-element optical array, a 120Hz screen assembly, and a multi-user head tracker. The display images for the left/right eyes are produced alternatively on a 120Hz direct-view LCD and are synchronized with the output of the projector, which acts as a backlight of the LCD. The novel steering optics controlled by the multiuser head tracker system directs the projector output to regions referred to as exit pupils, which are located in the viewers’eyes. The display can be developed in the "hang-on-the-wall"form.

• Journal of Digital Convergence
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• v.14 no.11
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• pp.283-288
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• 2016

This research is to study IoT based implementation of system and network for medical information processing. This paper's configuration environment consists of sensor node, gateway and server node as a basic IoT architecture. Medical terminal as a sensor node asks connect request to his server, and the server accepts the request if the medical device is already registered. Wearable medical device sends its collected sensing data to server, and server processes the received data for data visualization or saves them for usage in the future. This paper describes overall processes and their algorithms and suggests their software processing architecture.

• ETRI Journal
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• v.37 no.6
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• pp.1176-1187
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• 2015

This work proposes a highly efficient sensorless motor driver chip for various permanent-magnet synchronous motors (PMSMs) in a wide power range. The motor driver chip is composed of two important parts. The digital part is a sensorless controller consisting mainly of an angle estimation block and a speed control block. The analog part consists of a gate driver, which is able to sense the phase current of a motor. The sensorless algorithms adapted in this paper include a sliding mode observer (SMO) method that has high robust characteristics regarding parameter variations of PMSMs. Fabricated SMO chips detect back electromotive force signals. Furthermore, motor current-sensing blocks are included with a 10-bit successive approximation analog-to-digital converter and various gain current amplifiers for proper sensorless operations. Through a fabricated SMO chip, we were able to demonstrate rated powers of 32 W, 200 W, and 1,500 W.

• ETRI Journal
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• v.38 no.1
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• pp.112-122
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• 2016

This paper presents a set of candidate regulatory requirements for TV band devices (TVBDs) in the Rep. of Korea. To guarantee the protection of incumbent services, especially digital TV (DTV) and wireless microphones, in TV frequency bands, we suggest minimum separation distances of TVBDs from the noise-limited contour according to incumbent users and TVBD types. This paper also deals with multiple sets of separation distances of a co-channel TVBD network from a DTV protected contour on the basis of the radio propagation characteristics of different geographic areas to make good use of TV white space (TVWS) and safely protect the DTV service. We present a low-power transmission mode of TVBDs and the relevant separation distances for small-cell deployment. The service coverage reduction ratio of a TVBD network is investigated in the presence of DTV interference in four geographic areas. The TVWS field verification results, conducted on the island of Jeju (Rep. of Korea), show that incumbent services operate well without harmful interference from neighboring TVBDs with the proposed separation distances.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.12
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• pp.1198-1206
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• 2007

It is common to use PC or Digital picture frame in stand-alone fashion to view images, movies, or to listen MP3 musics which are considered as multimedia contents, However, such existing methods have weakness for expanding network requirements or augmenting extra data, in such case inevitably requiring external devices. With keeping in mind for such expansion, in this study, we have suggested a new concepts of network module which may utilize an image server for data transmission, in the proposed module, data alarm packet was defined for alerting incoming data from the image server and it became possible to synchronize between the image server and device not only in wired but also in wireless environments through UART. The method consists of a control module for an image server and a synchronization module between the server and the device. We have also tested the feasibility for future commercial usages such as advertisements through performance evaluations.

• Journal of Digital Contents Society
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• v.9 no.3
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• pp.509-516
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• 2008

We propose the Hybrid Rendering model to support multi-resolution for computer graphics. LOD method for computer graphics system considering performance of device environment and end-user preference usually adopts mesh resolution, mipmap in texture rendering, or oct-tree data structure in ray tracing. The hybrid rendering model, as a local shading model combining Gouraud shading model and a flat shading model, applies a proper shading method to each of polygons consisting of an object. This method can be an effective alternative to reduce real-time rendering time so that it can be utilized in real time adaptive service of computer graphic contents among various device environments under ubiquitous environments.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1110-1111
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• 2007

These days, the concerns about maintenance and repair of electric facilities for stable and reliable electric power supply are increasing day by day. Because, we can have enormous damages economically and socially from a problem of the facilities, no matter how it is a small one. Especially, electric facilities in our country had been built abruptly from 40 years ago, so it can be thought that here are great amount of old facilities that must be repaired or replaced with new one, and the number would be increased time by time. On this situation, many researchers are studying the efficient and reliable method of maintenance for electric facilities and the results are applied on the facilities gradually by growing interests of operators and managers of the facilities. In this paper, the IED(Intelligent Electronic Devices) for Diagnosis system of electric machines are described. It takes analog data from a sensing device and operates digital processor to get a optimum digital data for diagnosis system. Now, this device is applied on several high voltage substations to diagnose and maintain GIS. Brief schematic of total diagnosis system and the construction of the IED are included in this paper.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.10
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• pp.1787-1793
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• 2008

Fingerprint Recognition System is made up of Off-line treatment and On-line treatment; the one is registering all the information of there trieving features which are retrieved in the digitalized fingerprint getting out of the analog fingerprint through the fingerprint acquisition device and the other is the treatment making the decision whether the users are approved to be accessed to the system or not with matching them with the fingerprint features which are retrieved and database from the input fingerprint when the users are approaching the system to use. In this paper, we propose a new data structure, called Union and Division, for processing binarized digital fingerprint image efficiently. We present a minutiae extraction algorithm that is using Union and Division and consists of binarization, noise removal, minutiae extraction stages.

• Smart Structures and Systems
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• v.6 no.5_6
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• pp.661-673
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• 2010

This paper presents recent developments in an extremely compact, wireless impedance sensor node (the WID3, $\underline{W}$ireless $\underline{I}$mpedance $\underline{D}$evice) for use in high-frequency impedance-based structural health monitoring (SHM), sensor diagnostics and validation, and low-frequency (< ~1 kHz) vibration data acquisition. The WID3 is equipped with an impedance chip that can resolve measurements up to 100 kHz, a frequency range ideal for many SHM applications. An integrated set of multiplexers allows the end user to monitor seven piezoelectric sensors from a single sensor node. The WID3 combines on-board processing using a microcontroller, data storage using flash memory, wireless communications capabilities, and a series of internal and external triggering options into a single package to realize a truly comprehensive, self-contained wireless active-sensor node for SHM applications. Furthermore, we recently extended the capability of this device by implementing low-frequency analog-to-digital and digital-to-analog converters so that the same device can measure structural vibration data. The compact sensor node collects relatively low-frequency acceleration measurements to estimate natural frequencies and operational deflection shapes, as well as relatively high-frequency impedance measurements to detect structural damage. Experimental results with application to SHM, sensor diagnostics and low-frequency vibration data acquisition are presented.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.5
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• pp.49-57
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• 2010

The fault cryptanalysis is a physical attack in which the key stored inside of the device can be extracted by occurring some faults when the device performs cryptographic algorithm. Since the international signature standard DSA(Digital Signature Algorithm) was known to be vulnerable to some fault analysis attacks, many researchers have been investigating the countermeasure to prevent these attacks. In this paper we propose a new countermeasure to compute DSA signature that has its immunity in the presence of faults. Since additional computational overhead of our proposal is only an inverse operation in signature process, the proposed DSA scheme can be implemented more efficiently compared to previous countermeasures.