• 한국전자파학회논문지
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• 제28권12호
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• pp.1003-1006
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• 2017

본 논문에서는 실드 박스를 이용하여 다수의 휴대 단말기의 무선 성능을 시험할 경우, 발생하는 실드 박스 내 전기장 불균일 현상을 시뮬레이션을 통해 분석하였고, 전기장 균일도를 개선하기 위해서 두 가지 방법을 제시하였다. 제시한 방법들이 단말기 사이의 전기장 균일도를 크게 개선할 수 있음을 확인하였다.

• 한국디자인학회:학술대회논문집
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• 한국디자인학회 2001년도 Bulletin of The 5th Asian Design Conference International Symposium on Design Science
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• pp.8.1-8
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• 2001

• 전자공학회논문지
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• 제52권1호
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• pp.148-154
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• 2015

제 2세대 (2G) 휴대전화인 GSM (global system for mobile communication) 휴대전화는 pacemaker 및 ICD (implantable cardioverter defibrillator)의 기능에 영향을 미칠 수 있다고 보고가 되어 왔다. 이에 본 연구에서는 제 3세대 (3G) 휴대전화인 WCDMA (wideband code division multiple access) 휴대전화에서 방출되는 전자파가 pacemaker 및 ICD에 미치는 영향에 대해 알아보았다. 총 5개의 pacemaker 및 3개의 ICD를 대상으로 ECG simulator를 이용한 in-vitro 실험으로 진행하였다. 실제 WCDMA 휴대전화 대신 WCDMA 모듈 (평균 출력 : 0.25 W, 주파수 대역 : 1950 MHz)을 사용했다. WCDMA 모듈 전자파가 pacemaker 및 ICD에 미치는 영향을 평가하기 위해, 각 이식형 의료기기들을 WCDMA 모듈에 최대한 근접 (3 mm 이내) 시킨 후 5분간 전자파에 노출 시켰다. 실험 결과 WCDMA 모듈 전자파가 5개의 pacemaker 및 3개의 ICD에 미친 어떠한 영향도 관찰 할 수 없었다. WCDMA 휴대전화는 GSM 휴대전화보다 더 높은 주파수 대역 (1800-2200 MHz)에서 더 낮은 출력(0.01-0.25 W)을 방출하기 때문에, WCDMA 휴대전화에서 발생하는 전자파는 pacemaker 및 ICD 기기들에게 영향을 미치지 않을 것으로 사료된다.

• Human Ecology Research
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• 제56권4호
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• pp.391-405
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• 2018

There has been an increasing and widespread use of smartphones to make consumer purchases. Given the stark increases in the sales of business transactions using mobile phones, it is obvious that mobile phones have become major mediums for consumer purchases. Through mobile phones, people can make their purchases anytime, anywhere, which leads their impulse of consumption directly to actual actions of consumption. Consequently, mobile commerce has become widely spread and the competition of the market has intensified. The main findings and implications of this study are as follows. First, it is shown that, among the features of mobile commerce, elements of fun, usefulness, convenience, immediateness, and security affect mobile commerce user satisfaction. Second, among mobile commerce-related consumers' propensity, innovative consumption tendency appears to impact mobile commerce user satisfaction and repurchase intention. Third, recognition of elements in regards to fun, usefulness, convenience, immediateness, and security among features of mobile commerce affect consumers' intention to repurchase mobile commerce. Future recognition for mobile commerce has a direct impact on increasing consumers' repurchase intentions. Last, a higher mobile commerce user satisfaction leads to the higher repurchase intentions.

• ETRI Journal
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• 제29권1호
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• pp.107-109
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• 2007

In location-based services, most trigger technologies have been implemented on the server side by periodically requesting the locations of mobile phones from mobile network servers. However, bottlenecks and communication interruptions occur when the servers are overloaded by trigger requests. In this letter, we propose a new multilevel location trigger specification which distributes the event detecting role to mobile phones and redesigns the location triggering into a multilevel step. Our suggested location trigger specification can reduce bottlenecks caused by triggers in a mobile core network and reduce power consumption caused by embedded GPS devices in mobile phones.

• 산업경영시스템학회지
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• 제36권2호
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• pp.39-48
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• 2013

The development of mobile communication technology is transforming the market of mobile communication devices, which is used to be merely for simple communication, into the one which offers features of personal digital assistant (PDA), fax communication and Internet access. Unlike a mobile phone which comes out as a complete package and whose functions cannot be changed, a smart phone can be upgraded by its user, adding or removing apps as he pleases. OS's of smart phones are iOS-based Apple, Google Android, Window Mobile, and others. Due to its convenience and powerful features, many people use smart phones its high price. On the other hand, consumer complaints are rising on poor A/S for occasional malfunction. This study analyzes how A/S cases can be classified into groups according to quality factors. We evaluate factors such as consumer impression and consumer satisfaction. By dual quality evaluation using KANO method, we would like to show the different A/S strategy for smart phones, compared with mobile phones.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 학술대회지
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• pp.528-531
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• 2004

This paper presents the design and implementation of a QoS based IrDA in mobile phones. The IrDA standards have arised from the need to connect various mobile devices together. But currently, we have a difficult to connecting various mobile devices together. The difficult thing is to adjust the minimum turn around time. The minimum turn around time in IrDA deals with the time needed for a receiver circuit to recover following saturation by transmissions from the same device (turn around latency). This parameter corresponds to the required time delay between the last byte of the last frames sent by a station and the point at which it is ready the first byte of a frame from another station. This parameter comes into play when the link is turned around and is negotiated independency for each station. We solve this matter by using the Dynamic Adjustment Algorithm (DAA). The dynamic adjustment algorithm adjusts the minimum turn around time according to the numbers of devices. We apply our direct adjustment algorithm to our QoS based IrDA in mobile phones and show the improved performance of connection with various mobile phones together.

• ETRI Journal
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• 제41권3호
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• pp.337-347
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• 2019

The specific anthropomorphic mannequin (SAM) phantom was designed to provide a conservative estimation of the actual peak spatial specific absorption rate (SAR) of the electromagnetic field radiated from mobile phones. However, most researches on the SAM phantom have been based on early phone models. Therefore, we numerically analyze the SAM phantom to determine whether it is sufficiently conservative for various types of mobile phone models. The peak spatial 1- and 10-g averaged SAR values of the SAM phantom are numerically compared with those of four anatomical head models at different ages for 12 different mobile phone models (a total of 240 different configurations of mobile phones, head models, frequencies, positions, and sides of the head). The results demonstrate that the SAM phantom provides a conservative estimation of the SAR for only mobile phones with an antenna on top of the phone body and does not ensure such estimation for other types of phones, including those equipped with integrated antennas in the microphone position, which currently occupy the largest market share.

• 전자통신동향분석
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• 제37권3호
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• pp.74-84
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• 2022

The Korean mobile service market has persistently grown with the number of subscribers and volume of mobile traffic. It shows the slow diffusion of 5G subscribers, and rapid growth of both the MVNO(Mobile Virtual Network Operator) market and unlocked mobile phones. Therefore, this study derives the direction of telcos' strategies and policy implications by empirically analyzing the usage and attitude of LTE and 5G subscribers. Our major findings are as follows: First, our current mobile service subscription market constitutes most long-term customers for their incumbent carriers only by device change from lock-in with bundle services. Mobile tariffs, data speed, and benefits of bundle services are important factors affecting choices and customers' satisfaction with a provider and intentions of churning to another. Second, demand and satisfaction for using 5G are less because speeds and service tariffs act as pain points for 5G services. Third, the users' high preferences for MVNOs and unlocked mobile phones are linked to their subscription to MVNOs' low-cost plans with unlocked mobile phones on online channels. These streams lead to a big change in the market competition that MNO(Mobile Network Operator)s' market shares are expected to decrease and MVNOs' shares will be increased by two times, in the near future. Therefore, MNOs need to change their distribution strategies from offline to online channels and try to resolve the stereotype, "mobile tariffs are expensive," by enhancing their service values. Finally, as consumers prefer one-stop service in the same channel regardless of the distribution channel, policies should focus on the consumers' needs for convenience rather than on the channel separation for perfectly unlocked mobile phones.

• 대한인간공학회지
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• 제29권4호
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• pp.527-532
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• 2010

Product developers nowadays must consider not only the technological satisfaction of consumers but their affective needs as well. These affective needs are greatly affected by the appearance and performance functions of the product, which are simply called in this study appearance-based affection and performance-based affection. This study examined these two affective factors that must be considered while designing mobile phones. Extracted relationship between the two factors was processed in five steps. The first step includes gathering potential affective expressions that are needed to evaluate the levels of consumer's affection for mobile phone design in the pool of adjectives. In the second step, a simple frequency analysis was done from a consumer survey to extract frequently used affective expression. The third step was to extract primary tasks for mobile phones and to perform an experiment or a survey for the evaluation of mobile phones using those tasks. Representative affective factors were then extracted in the fourth step based on factor analysis. Finally, using ANOVA, the extracted representative affective factors were prioritized to draw a relationship between appearance-based affection and performance-based affection. The result of this study suggests each of appearance-based affections and performance-based affections that should be considered in designing mobile phones.