• Current Optics and Photonics
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• v.4 no.4
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• pp.336-344
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• 2020

Exact optical characterization of virtual and augmented reality devices using conventional luminance measuring methods is a time-consuming process. A new measurement method is proposed to estimate in a relatively short time the boundary of ray trajectories emitting from a specific position on a virtual images. It is assumed that the virtual image can be modeled to be formed in front of one's eyes and seen through some optical aperture (field stop) that limits the field of view. Circular and rectangular shaped virtual images were investigated. From the estimated ray boundary, optical characteristics, such as the viewing direction and three dimensional range inside which a eye can observe the specified positions of the virtual image, were derived. The proposed method can provide useful data for avoiding the unnecessary measurements required for the previously reported method. Therefore, this method can be complementary to the previously reported method for reducing the whole measurement time of optical characteristics.

• Journal of the Korean Society of Industry Convergence
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• v.22 no.6
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• pp.703-709
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• 2019

This paper proposes a monitoring and remote control system, an essential part of In Vehicle Infotainment (IVI) and Human Vehicle Interface (HVI) to provide safety and convenience to a driver. The system utilizes Bluetooth for a short range communication and utilizes WCDMA for a long range communication to enhance efficiency. In this paper, an integrated controller, which integrates a CAN communication module, a Bluetooth communication module, a WCDMA communication module, is designed to control a car. Also, a remote server for managing data is designed to provide real-time monitoring and remote control for a user via smart devices. Experiment results show that all the proposed remote control, driving log, real-time monitoring, and diagnostics functions are working properly. With the proposed system, a driver can drive safely by monitoring and inspecting a car before driving via smart devices, and control conveniently by controlling a car remotely.

• Electrical & Electronic Materials
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• v.7 no.2
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• pp.107-116
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• 1994

In the manufacturing of VLSI circuits, variations of device characteristics due to the slight differences in process parameters drastically aggravate the performances of fabricated devices. Therefore, it is very important to establish optimal process conditions in order to minimize deviations of device characteristics. In this paper, we used one-dimensional process simulator, SUPREM-II, and two dimensional device simulator, MINIMOS 4.0 in order to extract optimal process parameter which can minimize changes of the device characteristics caused by process parameter variation in the case of short channel nMOSFET and pMOSFET device. From this simulation, we have derived the dependence relations between process parameters and device characteristics. Here, we have suggested a method to extract process parameters from design trend curve(DTC) obtained by these dependence relations. And we have discussed short channel effects and device limitations by scaling down MOSFET dimensions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.9
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• pp.2167-2173
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• 2013

Recently, people are paying huge attention to problems caused by indoor air pollution. Also, the need for the system that monitors environmental information for indoor and warns a danger is growing increasingly. In this regard, we designed and implemented environment monitoring system for indoor. In this paper, we describe the system with hardware elements and it's communication method. In order to transfer the data from environment sensors, we use short-range wireless communication in smart phone. The proposed system is possible to know the indoor environment information in installed sensor node. If the risk is found, For the proposed system, there is an advantage that may be appropriate evacuation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.530-532
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• 2015

Nowadays, it is animately studied on IoT(Internet of Things) on the strength of development of the short-range communications technology and smart device. In this paper, it made a interface board which is capable of short-range communications networks based on embedded linux and Android OS (operating system). and we also made a IoT sensor module and device driver module. This devices are easily separated and changed and also simply embodied in IoT, and It was implemented using the Android app that allows you to control the sensors.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.8
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• pp.549-554
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• 2003

In this paper, we have designed and implemented by a monolithic microwave integrated circuit(MMIC) of a 5.8GHz-band low noise amplifier (LNA) composed of receiver front-end(RFE) in a on-board equipment system for dedicated short range communication. The designed LNA is provided with two active devices, matching circuits, and two drain bias circuits. Operating at a single supply of 3V and a consumption current of 18mA, The gain at center frequency 5.8GHz is 13.4dB, NF is 1.94dB, Input IP3 is -3dBm, S$_{11}$ is -18dB, and S$_{22}$ is -13.3dB. The circuit size is 1.2 $\times$ 0.7 $\textrm{mm}^2$.>.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.21-24
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• 2001

Bluetooth wireless technology is a publicly available specification proposed for Radio Frequency (RF) communication for short-range and point-to-multipoint voice and data transfer. It operates in the 2.4GHz ISM(Industrial, Scientific and Medical) band and offers the potential for low-cost, broadband wireless access for various mobile and portable devices at range of about 10 meters. In this paper, we describe the structure and the test results of the bluetooth baseband module we have developed. This module has a UART interface for HCI and a audio codec for voice. The interface between controller and this module supports common control interface. An FPGA implementation of this module is tested for file and bit-stream transfers between PCs.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.7
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• pp.69-76
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• 1995

A new device structure has been developed for p-i-n switches. In this structure, the phosphorus-diffused n$^{+}$ layter adjacent to the boron-doped anode is used to short the p$^{+}$ anode-channel(i-region). This change in the anode electrode structure results in a significant improvement in the threshold voltage-to-holding voltage($V_{Th}/V_{h}$) ratio, which is due to the suppression of the hold injection from the anode by the n$^{+}$ layer. The shorted anode p-i-n devices of a 100 .mu.m channel length show an extremely high threshold voltage in the 250~300 V range and a low holding voltage in the 5~9 V range. These features of the device are expected to acdelerate their practical application to power switching circuits.

• Journal of Communications and Networks
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• v.6 no.2
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• pp.163-172
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• 2004

Ultra Wide Bandwidth (UWB) spread-spectrum techniques will playa key role in short range wireless connectivity supporting high bit rates availability and low power consumption. UWB can be used in the design of wireless local and personal area networks providing advanced integrated multimedia services to nomadic users within hot-spot areas. Thus the assessment of the possible interference caused by UWB devices on already existing narrowband and wideband systems is fundamental to ensure nonconflicting coexistence and, therefore, to guarantee acceptance of UWB technology worldwide. In this paper, we study the coexistence issues between an indoor UWB-based system (hot-spot) and outdoor point to point (PP) links and Fixed Wireless Access (FWA) systems operating in the 3.5 - 5.0 GHz frequency range. We consider a realistic UWB master/slave system architecture and we show through computer simulation, that in all practical cases UWB system can coexist with PP and FWA without causing any dangerous interference.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.24.1-24.1
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• 2010

In practical operation, the exposed surfaces may get dirty thus degrade the performance of devices. So the combination of self cleaning and antireflection is very desirable for use in outdoor photovoltaic and displaying devices, self cleaning windows and car windshields. For the purpose of self cleaning, the surface needs to be either superhydrophobic or superhydrophilic. However, in practice AR in the visible region and self cleaning are a pair of competitive properties. To satisfy the requirements for superhydrophobic or superhydrophilic surfaces, high surface roughness is required. But it usually cause severely light scattering. Photo-responsive coatings (TiO2, ZnO etc.) can lead to superhydrophilic. However, the refractive indices are high. Thus for porous structure, controlling pore size in the underwavelength scale to reduce the light scattering is very crucial for highly transparent and self cleaning antireflection coating. Herein, we demonstrate a simple method to make high performance broadband antireflection layer on the glass surface, by "carving" the surface by hot alkali solution. Etched glass has superhydrophilic surface. By chemical modification, it turns to superhydrophobic. Enhanced transparency (up to 97%) in a broad wavelength range was obtained by short time etching. Also antifogging effect has been demonstrated, which may offer advantage for devices working at high humidity environment or underwater. Compositional dependence of the properties was observed by comparing three different commercially available glasses.