• 전기학회논문지
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• 제64권1호
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• pp.78-81
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• 2015

This paper investigates the performance of phone case with different permittivities like plastic, urethane and silicone. Then, we put an electromagnetic band gap (EBG) structure in phone case to reduce the specific absorption rate (SAR). In order to design the phone case, a loop antenna for PCS 1900 band was used. The phone case consists of a hairpin-like EBG structure that is more compact than other EBG structures. The SEMCAD X fdtd simulation results showed that, this proposed phone case can reduce SAR by 13 - 30% at similar power that is radiated by the antenna. This phone case can be used in future to reduce the SAR from mobile phones.

• 한국CDE학회논문집
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• 제17권6호
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• pp.398-408
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• 2012

This paper investigates the tolerance stack-up in a commercial sliding-type mobile phone model developed by a Korean electronics company, with focus on the dimensional quality of the gap between the sliding top and the main body. The tolerance analysis in this study is done using a commercial software package, which runs Monte Carlo simulations to produce the statistical distributions of the gap size at desired locations. Such an analysis revealed that the original design did not yield the desired dimensional quality of the gap. Through a series of systematic analyses and syntheses, an improved design is proposed for the nominal dimensions and tolerances of selected features of the parts. The proposed design was validated, through tolerance analysis simulation, to meet the desired requirement of the gap quality.

• 대한인간공학회지
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• 제29권4호
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• pp.541-546
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• 2010

The gesture 'Flick' is the most fundamental and important part for efficient interactions in the touch screen that are being extensively applied to mobile phones. This study investigated users' satisfaction of the flick operation in representative touch phones, and measured their performances with established three measures: gap between finger and initial cursor, the number of moved lists per 0.2 seconds, and the number of moved lists after ten continuous flicks. The measurement was performed with high speed camera and motion analysis software. The flick movement in mobile phone with high users' satisfaction showed that the gap between finger and cursor positions was less and the speed reached high within 0.6 seconds quickly and then was drastically slow down. Especially, maximal and common time intervals between continuous flicks were measured with an experiment. Based on the evaluation and measurement, several design guidelines for efficient flick performances were suggested.

• Journal of the Optical Society of Korea
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• 제19권6호
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• pp.658-664
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• 2015

Lens designers generally refer to flat image fields and attempt to minimize the field curvature. Present-day CMOS image sensors for mobile phone cameras, however, are not flat, but curved. Sometimes it is necessary to generate an intentional field curvature according to the degree and direction of the CMOS image-sensor’s curvature. This paper presents the degree of curvature of a CMOS image sensor measured using an interferometer, and proposes an effective compensation method that minimizes the net field curvature through optimizing the air gap between lens elements, which is demonstrated using simulations and experiments.

• 대한인간공학회지
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• 제34권1호
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• pp.11-18
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• 2015

Objective: The aim of this study was to understand the effects of phone weight on the typing performance and muscle recruitment in the neck and upper extremity while typing a text message with dominant hand. The iPhone4 and iPhone5 were compared due to their 28-gram differences in weight. Background: Too much use of a cellular phone can lead the musculoskeletal disorders in the upper extremity. Phone makers tend to make their new models bigger, lighter, faster and smarter. Method: Fourteen healthy volunteers without any history of neuromuscular disorders or ongoing pain who used their smartphone more than one year were recruited. A 112g phone (iPhone5) and a 142g phone (iPhone4) were used for typing the lyric of the Korean national anthem with their dominant hand. Typing duration, the typing error, the perceived fatigue, and preference was investigated. Muscle recruitment and the resting gap of neck (middle trapezius and levator scapula), shoulder (infraspinatus and mid deltoid), elbow (biceps brachii and brachioradialis), thumb (extensor and abductor policis brevis) were collected using surface electromyography. Typing error was counted and typing speed was calculated in characters per min. The data were analyzed using a paired t-test and chi-square (${\chi}^2$) analysis for the effects of phone weight on the typing performance parameters and muscle recruitment. Results: Typing text message with iPhone5 took longer but had less muscle recruitment in brachioradialis, and extensor policis brevis muscles. Lighter weight of iPhone5 made biceps brachii to rest less without increasing the mean %EMG. Conclusion/Application: Findings of this study can be valuable information for phone designers to develop more productive device and for smartphone users to prevent the musculoskeletal disorders in the upper extremities.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2013년도 추계학술발표대회
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• pp.368-371
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• 2013

자전거 인구가 증가함에 따라 4대강, 한강 등 10대 자전거 거점도시를 중심으로 인프라가 구축되고 있다. 이러한 인프라로 급속히 성장된 자전거 인구가 약 1,000만 명 에 이르지만, 이러한 유저간의 정보제공 및 정보공유를 뒷받침 해줄 복합적인 콘텐츠가 부족한 실정이다. 하여 본 연구에서는 정보기술로 급속하게 성장하고 있는 스마트폰과 SNS을 기반으로 하여 자전거 노선 공유, 거리 및 속도 분석, 자전거 모임 제공, 여행지 공유 등을 서로 공유하고 제공할 수 있는 자전거 문화 활성화 서비스를 구현하였다.

• 대한한의학원전학회지
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• 제30권3호
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• pp.133-141
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• 2017

Objectives : As of 2013, South Korea ranked number one in the world in smartphone penetration rate with 67.6%. Unfortunately, with the rise of smart phone use, side effects such as fraud, loss of personal information, identity theft, formation and widening of a mobile information gap, and last, but not least, smart phone addiction, also increased. Methods : Seventh (7th)graders from a girls' junior high school in Seoul, the capital of South Korea, we reevaluated the Smart phone Addiction Proneness Scale (S-scale). Among the 9 students classified as high risk users, 5 were randomly selected for a study group, and the remaining 4 students, meanwhile, were designated as a control group. The study group received Korean medicine music therapy (KMMT) in a total of 8 sessions, each session lasting 50 minutes. Both pre- and post-interventions, the two groups completed the S-scale, Harris and Harris' concentration grid exercise, STAI, and STAXI-K. We analyzed the data by t-test and paired t-test using IBM SPSS Statistics. Results : KMMT had a significant influence on proneness to smart phone addiction (t=3.130, p=.035). KMMT had positive effects on concentration improvement (t=-2.935, p=.043), trait-anxiety symptoms improvement (t=2,992, p=.040), and anger-expression control (t=4.416, p=.012). Conclusions : KMMT had positive, improving effects on trait anxiety and anger expression, which in turn enhanced the improvement of concentration as well as the decrease of smart phone-addiction proneness.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2012년도 춘계학술대회
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• pp.429-432
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• 2012

애플(Apple) 아이폰(iPhone)으로 시작된 모바일 기기보급은 구글(Google) 안드로이드(Android)가 등장하면서 확산되었다. 최근들어 모바일기기 범위는 아이폰과 안드로이드, 바다(Bada), 윈도우폰 7(WindowPhone7), 블랙베리(BlackBerry)등 스마트폰과 아이패드(iPad)와 안드로이드기반 태블릿 (Tablet)등으로 다양해졌다. 과거에는 특정 기기에 맞는 전용 어플리케이션(Application, 이하 앱)만 개발하면 되었지만, 현재는 다양한 운영체제의 특성을 고려하여 개발하여야만 한다. 그에 따라 많은 문제점이 발생하고 기존 개발방법과 다른 개발방법들이 등장하였다. 본고에서는 이런 개발방법중 원소스멀티유즈(One Source Multi Use)를 지향하는 모바일 하이브리드앱(Mobile Hybrid App) 개발도구에 대해 알아보고 하이브리드앱 개발도구의 차이점을 비교하여 상황에 맞는 개발방법을 제시한다.

• 융합보안논문지
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• 제12권1호
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• pp.63-70
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• 2012

오늘날 스마트폰 시장이 폭발적으로 성장함에 따라 일반인과 시각 장애인의 스마트폰 사용에 차이가 발생하여 정보 활용 격차가 날로 심화되고 있다. 본 논문에서는 시각 장애인의 일반인과의 정보 활용 격차를 줄이기 위해 시각 장애인만을 대상으로 한 저렴한 가격의 요철 필름을 사용한 점자를 기반으로 문자 및 숫자 입력 시스템을 제안한다. 제안된 시스템은 점자의 모양을 기반으로 애플의 iOS 상에 요철 필름과 레이아웃을 설계하여 그 레이아웃에 따라 점자 및 숫자 키보드를 설계하였고, 부가적으로 전화, 문자, 단축 다이얼, 응급 구조를 위한 위치전송 기능을 설계하였다. 점자 키보드를 이용하여 입력한 문자는 자동으로 클립보드로 복사되며 다른 응용에서도 이용할 수 있게 하여 시각 장애인이 스마트폰을 편리하게 사용할 수 있도록 구현 하였다.

• 한국기계가공학회지
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• 제15권6호
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• pp.9-15
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• 2016

Due to material-specific vulnerabilities, the surfaces of the liquid crystal glasses used in mobile phones can crack easily, with even the smallest cracks undergoing propagation. To protect the glass surfaces, films are attached to the surfaces during the mobile phone production process. However, after machining the liquid crystal, removal of the film on the liquid crystal surface using chemical and mechanical methods is required. In this research, a peeling apparatus was developed for removing the films attached to liquid crystal surfaces during the production process. Mechanical attachment and design automation through experimentation and finite element modelling were performed to confirm the validity of the design.