• 한국콘텐츠학회논문지
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• 제7권11호
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• pp.102-110
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• 2007

본 논문에서는 UHF대역 중 900MHz 대역에서 동작하는 휴대용 RFID 리더를 설계하고 제작하여 그 제반 특성을 측정을 통하여 분석하였다. 측정 결과의 분석은 EPC Global에서 제안한 EPC Class 0 표준을 기준으로 수행되었다. 제안하는 RFID 리더는 약 11kbps의 속도로 태그와 데이터 통신을 수행하며, RF 최대 출력은 20dBm이다. 제안된 휴대용 RFID 리더는 초당 최대 68개의 태그를 인식할 수 있으며, 리더의 출력 전력이 20dBm인 경우 최대 인식 거리는 30cm 이다. 그리고 전체적인 크기는 $71mm{\times}55mm$로서 상용 제품과 비교했을 때 최대 90%, 최소 14% 감소된 것이다.

• 산업경영시스템학회지
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• 제30권2호
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• pp.15-22
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• 2007

By the early 20 century, "workman" introduced by SONY was the leading portable analog sounder. However, at the same century, workman was pushed out from the portable sounder by iRiver developed by MPMAN.COM. This portable digital sounder is called MP3-Player (MP3P), and has become the most popular portable digital sounder in the current market. This study combined two customer satisfaction models, mobile internet customer satisfaction model (Yu, 2002), and portable communication customer satisfaction model (Bae, 2003), in order to empirically test consumption of MP3P and its satisfaction. The proposed model tested four constructs, company's image, product price, product design and product function, influencing customer satisfaction, which leads to affect customer loyalty. 267 survey responses were analyzed by using structural equation modeling (SEM). The results show that all constructs had significant impact. This study suggests a good understanding of consumer satisfaction and loyalty of MP3P and the future direction of MP3P research regarding to consumer satisfaction.

• 센서학회지
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• 제13권1호
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• pp.41-46
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• 2004

There is currently much interest in the development of instruments that emulate the senses of humans. Increasingly, there is demand for mimicking the human sense of smell, which is a sophisticated chemosensory system. An electronic nose system is applicable to a large area of industries including environmental monitoring. We have designed a protable electronic nose system using an array of commercial chemical gas sensors for recognizing and analyzing the various odours. In this paper, we have implemented a portable electronic nose system using an array of gas sensors for recognizing and analyzing VOCs (Volatile Organic Compounds) in the field. The accuracy of a portable electronic nose system may be lower than an instrument such as GC/MS (Gas Chromatography/Mass Spectrometer). However, a portable electronic nose system could be used on the field and showed fast response to pollutants in the field. Several different algorithms for odours recognition were used such as BP (Back-Propagation) or LM-BP (Levenberq-Marquardt Back-Propagation). We applied RBF (Radial Basis Function) Network for recognition and quantifying of odours, which has simpler and faster compared to the previously used algorithms such as BP and LM-BP.

• 한국전자통신학회논문지
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• 제16권3호
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• pp.477-484
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• 2021

본 연구를 통해 설계된 Portable ESS를 위한 4kW급 인버터는 휴대용에 걸맞게 수동소자(캐패시터, 인덕터 등)의 부피를 줄여 경량화 및 높은 전력밀도를 달성하고, MOSFET의 낮은 온저항을 통해 MOSFET의 열손실을 최소화하여 높은 효율을 달성할 수 있도록 했다. 또한, 높은 품질의 에너지 전달을 위해 현행 한전 영업업무처리지침기준에 따라 낮은 THDV를 가지도록 설계되어 왜곡이 낮은 정현파가 출력되도록 설계되었다.

• Journal of information and communication convergence engineering
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• 제20권1호
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• pp.49-57
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• 2022

Fertilizers have long been used to increase crop yields; however, farmers are still having difficulties in managing fertilizers for growing crops as well as economic problems. The conventional method of soil sampling and laboratory analysis to determine soil pH is time consuming and costly; therefore, a portable pH sensor is developed to characterize spatial or temporal variability within fields via rapid and dense data acquisition. The portable pH sensor comprises an electrode unit, a portable console, and a USB connector. The soil water content (SWC) and electrical conductivity (EC) affect the electrical resistance of soil. An artificial test soil is performed to evaluate the effect of SWC and EC on soil pH. The test results show that stable pH measurements are achieved at SWCs greater than 20 mL (16.3%). Regardless of the SWC, the electric potential difference (EPD) remains at 2.5 g of NaCl. As the EC increases in the soil samples, the EPD increases.

• 한국컴퓨터정보학회논문지
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• 제26권6호
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• pp.63-71
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• 2021

본 논문에서 운용자의 지속적인 작업 없이 휴대용탐지장치의 기능 및 성능시험을 원격으로 수행하기 위한 무인자동화시험시스템의 설계 개선을 위해 TRIZ 방법론의 기술적 진화법칙(TESE, Trends of Engineering System Evolution)을 적용한 방안을 제안한다. 시험에 소요되는 시간과 비용을 고려하여 휴대용탐지장치 한 대당 소요되는 시간 비용을 최소화하고 한번 시험시 최대한 많은 수의 휴대용탐지장치를 시험할 수 있도록 개선된 효율적인 설계 개발 방안을 도출한다. 또한 설계된 구조와 개선된 설계 구조에 대한 3D 모델링 형상을 설계하여 설계 개선 전과 후의 무인자동화시험시스템을 비교한다. 여기서 제안된 방안을 적용한 무인자동화시험시스템은 기존 시험시스템의 여러 가지 단점들을 해결함으로써 이상성을 높이고 휴대용탐지장치의 기능 및 성능시험 효율을 향상시킬 수 있을 것으로 기대된다.

• 한국의류학회지
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• 제47권1호
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• pp.1-16
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• 2023

The smart fashion industry is showing steady growth worldwide, which will create new value throughout the fashion industry and become an essential element for efficient lifestyles. This study attempted to examine the development trend of smart fashion products from a design perspective and present the direction of design as a fashion item incorporating smart technology from a functional perspective. For this purpose, the category of portable smart fashion and the characteristics of the research object were considered through current status survey and previous research review. Among smart fashion, accessories and clothing/fabric products that have been released thus far that apply portable fashion design principles are selected and its characteristics are analyzed. In addition, function keywords were extracted based on the product description provided by the manufacturer and the function-oriented types were classified to identify each type's design characteristics. Therefore, the area receiving the signal and the sensor size should be considered, as should the fashion accessory type that combines various materials and colors. The clothing/textile type requires a design that mainly focuses on functions related to bio-signal interactions.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 V
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• pp.2871-2874
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• 2003

The development of a portable system to be used by diabetes patients and renal discase patients is needed to monitor their urea concentration and their glucose concentration in blood. This paper reports a compound sensor composed of a urea sensor, a glucose sensor and a micro-channel. This paper also reports the development of a portable measurement system to measure the concentrations, display the values, and save the values to be used by doctors.

• Journal of Information Technology Applications and Management
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• 제12권4호
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• pp.59-70
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• 2005

Flash memories are one of best media to support portable computer's storages in mobile computing environment. The features of non-volatility, low power consumption, and fast access time for read operations are sufficient grounds to support flash memory as major database storage components of portable computers. However, we need to improve traditional transaction management scheme due to the relatively slow characteristics of flash operation as compared to RAM memory. in order to achieve this goal, we devise a new scheme called Flash Two Phase Locking (F2PL) scheme for efficient transaction processing. F2Pl improves transaction performance by allowing multi version reads and efficiently handling slow flash write/erase operation in lock management process. We also propose a simulation model to show the performance of F2PL. Based on the results of the performance evaluation, we conclude that F2PL scheme outperforms the traditional scheme.

• 한국정보통신학회논문지
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• 제5권6호
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• pp.1151-1156
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• 2001

본 논문에서 이동통신 전화기에 의해 인체두부에 유기된 전계 분포와 지향성을 분석하였다. 계산된 모델은 인체 두부모델을 구성하고 안테나는 휴대폰 크기와 같은 그라운드판위에 올려놓았다. 이동 통신 전화기의 안테나로 전기력선이 제한 받지 않는 용량을 장하한 QMSA를 활용하였다. 안테나는 2㎓ 부분의 주파수 대역에서 동작하도록 설계하였고, 인체 두부로 터의 거리에 따른 변화와 안테나 복사 특성을 고찰하였다.