• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.5
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• pp.401-408
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• 2013

Dual-layer differential codebook using 8-PSK (phase shift keying) constellation as its codeword elements, is proposed for Long term evolution (LTE) and/or LTE-Advanced systems. Due to the temporal correlation of the adjacent channel matrices, the consecutive precoding matrices are likely to be similar. This approach quantize only the differential information of the channel instead of the whole channel subspace, which virtually increase the codebook size to realize more accurate quantization of the channel. Especially, the proposed codebook has the same properties of LTE release-8 codebook that is, constant modulus, complexity reduction, and nested property. The mobile station can be designed by using less expensive non-linear amplifier utilizing constant modulus property. Computer simulations show that the capacity of the proposed dual-layer codebook performs almost 1.2dB better than those of any other non-differential codebooks with the same amount of feedback information.

• The Journal of Society for e-Business Studies
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• v.22 no.3
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• pp.43-55
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• 2017

The market for medical tourism services in the world is steadily increasing and the medical tourism market in the South Korea is also showing high growth. However, they have also problem such as informal various information and services, irregularity price competition etc. In order to solve this problem, We have designed a medical tourism service model based on ICT specific on domestic medical ecosystem. First, analysis trends of domestic and overseas medical ecosystem and identify current problem of medical tourism. In order to solve existed problem we also have designed a medical tourism strategy. Based on the strategy, we have designed business service model based on ICT platform for as fit as Korea medical tourism status. The proposed medical tourism business service model can provide usability to customer and also can solve current medical tourism problem. We expect industrial effect and contribution to the activation.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.6
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• pp.1089-1096
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• 2019

Recently, small-scale IoT services using a small amount of information through low-performance computing have been spread. It requires low cost, low-power, and long-distance communication technologies with wide communication radius, relatively low power consumption. This paper proposes a MAC layer and routing protocol that supports multi-hop transmission in small-scale IoT environment distributed over a large area based on LoRa communication and delivering a small amount of sensing data. The terminal node is mobile and the communication type provides bidirectional transmission between the terminal node and the network application server. By applying the proposed protocol, a production line monitoring system for smart factory was implemented. It was confirmed that the basic monitoring functions are normally performed.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2007.05a
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• pp.132-135
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• 2007

본 연구에서는 브랜드 개성이 제품의 개성을 판단하는데 영향을 미치는가에 대하여 설문을 통해 살펴보았다. 동일한 제품에 대하여 개성이 상이한 브랜드가 적용되었을 경우 제품의 개성을 판단함에 있어 브랜드 개성의 특성이 반영되는지 여부를 확인하고자 하였다. 설문을 위하여 두 켤레의 신발을 준비하였으며 각각은 상징적인 측면이 강조된 여성용 하이힐 제품과 기능적인 측면이 강조된 운동화로 구성하였다. 각 제품에 대하여 명품브랜드(Versace), 일반 상용 브랜드(독일: C&A, 한국: 밀리오레), 그리고 브랜드가 부착되지 않은 총 6장의 사진을 준비하였다. 실험에 앞서 별도의 피험자들이 상기 사용된 브랜드들에 대하여 "frohlich/유쾌함(cheerful)", "ehrlich/정직함(honest)", "provokativ/도발적인(provocative)"의 형용사로 평가를 하였다. 본 실험에서는 실험참여자에게 각 신발들의 3가지 사진 중 무작위로 선정된 사진을 한 장씩 보여주고, 각각에 대해 브랜드 측정에 사용했던 동일한 평가항목을 이용하여 평가하도록 했다. 더불어, 본 연구는 개인주의 문화권에 비하여 집단주의 문화권에서 브랜드의 영향이 더 두드러지게 나타나는 지를 알아보기 위하여 독일의 만하임대학(Universitaet Mannheim)과 한국의 한국과학기술원(KAIST) 학생들을 위주로 설문을 실시하여 문화적 차이에 따른 브랜드 영향력을 비교하고자 하였다. 실험결과에서는 독일과 한국 모두에서 브랜드 개성이 제품 개성에 유의한 영향을 미치지 않는 것으로 나타났으나, 브랜드 개성이 제품의 기능적 측면(가격)에는 영향을 미치는 것으로 나타났다(p<.001).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.6
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• pp.1229-1236
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• 2009

Puretone audiometer, which is a machine used for measuring the minimum hearing threshold, can be cost-effectively implemented using computer with sound card and software. In this paper, we describe a puretone audiometer which has been designed and implemented based on a general PC with sound card. It supports air conduction and bone conduction test taking with automatic masking. It also provides multiple modes consisted of self-test, auto-test and manual test mode. Such multiple modes makes it possible to use in various environments like as home and/or hospital. Through measure of waveform of output voltage and sound pressure, we verified that puretone audiometer of this paper properly operates.

• Korean Journal of Cognitive Science
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• v.22 no.1
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• pp.1-18
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• 2011

With rapid spread of handheld devices like cellular or smart phones, a short message service (SMS) comes on the public as a communication means. SMS is very cheap and can be easily written down on the storage in order not to forget it, hence it is widely used to inform schedules (time and place). In this paper, we develop a system for automatically registering schedules extracted from SMS text messages. SMS text messages are very short and concise, but include a lot of Internet words like slangs and abbreviations. These have made it difficult to extract information on schedules from them. Also handheld devices have some limitations on computing power and storage and then applying general natural language processing modules like morphological analysis to the devices are somewhat hard. To relax these burdens, we extract schedule informations from SMS messages using machine learning methods like condition random field (CRF) without using any language processing modules and register the informations on the schedule management system of handheld devices. Our proposed automatic schedule registration system has implemented on Samsung Omnia phone for experiments.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.12
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• pp.1397-1404
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• 2014

Grab cranes are used for multi-purpose when the sand and soil are deposited into harbor wharf or the undersea construction is performed. Among the components of crane grab, the wire drum and disc brake pad are key expendables and have disadvantages that lot of heat is generated and very expensive when replacing them. In this study, the thermal image analysis for the disc brake, which works with wire drum of the crane is suggested. The suggested system performs the pad thermal diagnosis through the thermal image using the characteristics that the disc and pad surface temperatures are distributed abnormally before the brake failure and the disc pad damage. Therefore, the damage by the failure can be prevented by discovering the abnormality of the machine parts before failure and the life cycle of the pad and the cost can be extended and saved by operating the crane performing constant checkup for the overload.

• The Journal of the Korea Contents Association
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• v.10 no.2
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• pp.412-420
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• 2010

With increased complexity of product and market, the phenomenon that a consumer get paradoxical attitude toward marketing object has been increased. And this phenomenon eventually affects the relationship between consumer and product. In this study we tried to find more paradoxical phenomenon and understand consumer behavior confronting these situations when they buy agro-product based on ground theory methodology. According to the results, consumer's expectation and purchase experience can promote quality paradox experience during confronting various marketing activities such as price, product, promotion, place. Also these experience can cause quality paradox related interaction and communication even though there could be differences in their experience according to demographic characteristics, personal preference, and risk perception. Consumer will develop multiple strategies against quality paradox to manage the uncomfortable paradox experiences.

• Clean Technology
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• v.17 no.3
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• pp.191-200
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• 2011

Natural polymers, biopolymers, and synthetic polymers based on renewable resources are the basis for the 21th portfolio of sustainable and eco-friendly plastics but high-volume consumable plastics continue to be dominated by nondegradable petroleum-based materials. Three factors have recently made biodegradable polymers economically attractive: (i) rising costs of petroleum production resulting from the depletion of the most easily accessible reserves, (ii) environmental and economic concerns associated with waste plastics, and (iii) emissions of carbon dioxide from preparation of petroleum-based materials. These pressures have driven commercial applications based on biodegradable polymers which are related to reduction of carbon dioxide in processing, such poly(hydroxy alkanoate) and poly (lactide). Since initial degradation of these polymers leads to catastrophic mechanical failure, it is necessary to control the rate of initial degradation for commercial applications. In this article, we have a critic review on the recent progress of polymer modification for the control of degradation.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.553-553
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• 2013

상압 플라즈마 기술은 표면처리, 온존 발생장치, VOC (Volatile Organic compound) 제거등 다양한 산업분야에서 응용되고 있다. 상압플라즈마 기술 또한 DBD (Dielectric barrier discharge), Griding Arc, SDIP (Surface Discharge Induced Plasma) 등 다양한 기술들이 개발되어져 왔다. VOC를 제거하기 위한 다양한 플라즈마 기술중 특히 BDB 방법과 SDIP 기술들은 플라즈마에 의한 VOC 분해 뿐만 아니라 오존 발생을 통하여 VOC성분을 분해하는 것으로 알려져 있으며 효율이 매우 뛰어난 것으로 보고 되고 있다. 그러나 BDB 방전의 경우 방전이 발생하는 간격이 매우 작아 공기를 정화시키기 위해 좁은 유로를 통하여 일정넓이를 이동하여하 하기 때문에 압력감소가 심하며 이를 개선하기위해 다단으로 설계할 경우 구조가 복잡하고 가격이 고가인 단점이 있다. 본 연구에서는 두 개의 면 전극이 마주보는 형태로 된 DBD 구조의 단점을 보완하기 위하여 빗살무늬 모양의 다층구조의 선형전극으로 구조를 변화시켜 전극에 의한 압력감소를 방지하고 효율적으로 플라즈마 및 오존을 발생시킬 수 있는 VOC제거용 상압 플라즈마 발생장치를 개발하였다. 또한 플라즈마 발생 및 오존발생량이 우수한 것으로 알려져 있는 SDIP 장치 또한 제작하여 비교 평가를 하였다. 제작된 플라즈마 발생장치는 60 Hz와 20kHz의 교류 고압파워 서플라이를 이용하여 플라즈마 발생실험을 진행하였다. 선행 연구에서는 60 Hz의 고압 파워 서플라이를 이용하여도 플라즈마 방전이 잘 된다고 보고되었는데 본 실험에서 60 Hz 파워 서플라이를 사용할 경우 15 kV 이상이 인가될 때 아주 약하게 오존이 발생하는 현상이 관찰되었으나 육안으로 구분이 될 만큼의 플라즈마 방전은 발생하지 않았다. 20kHz의 고압파워 서플라이를 사용한 경우에는 비교적 낮은 전압인 7 kV에서 방전이 관찰되었으며 분당 22 mg의 오존이 발생하였다. SDIP를 이용한 경우 플라즈마가 발생하는 조건은 SDIP의 기하학적 형상에 많이 의존하게 된다. 본 실험에 SDIP 장치는 매우 낮은 전압에서 방전을 시작하였다. 기존의 DBD와는 다르게 1.7 kV에서 플라즈마 발생하였으며 1.8 kV에서 정상적인 플라즈마 방전이 발생하였다. 이때 분당 3.1 mg의 오존이 발생하였다. 오존 발생양은 앞에 빗살형 플라즈마 방전장치에 비하여 낮은데 인가되는 전력을 고려하면 입력된 전기 에너지당 오존발생양은 비슷한 수준이였다.