• ETRI Journal
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• v.38 no.4
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• pp.776-786
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• 2016

The fairly recent standard of equipping mobile devices with advanced imaging sensors has opened the possibility of conveniently diagnosing skin conditions, anywhere, anytime. For this application, we attempted to estimate skin conditions from a skin image taken by a mobile handheld camera. To estimate the skin conditions, we specifically identified three skin features (pigmentation, pores, and roughness) that can be measured quantitatively from a skin image. The experimental data indicate that the existing thresholding methods are inappropriate for extracting the pigmentation and pore skin features. Thus, we propose a new line-fitting based thresholding method for skin feature detection. We thoroughly evaluated our proposed skin condition estimation method using our skin image database. The experimental results show that our proposed thresholding method can better determine the threshold leading to the most visually plausible detection, when compared to existing methods. We also confirmed that skin conditions can be feasibly estimated using a common mobile handheld camera (for example, a smartphone).

• Convergence Security Journal
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• v.9 no.2
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• pp.85-89
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• 2009

This study to solve these problems a search system has been designed by combining the two methods. Also the search and manage image data by handheld devices such as portable PDA or smart phone, a system has been designed application to an embedded system. Once this is used, multimedia data can be efficiently searched and utilized by handheld devices.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10e
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• pp.151-153
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• 2002

Mobile handhold devices such as PDA(Personal Digital Assistant) and Cellular Phone are more and more popular for personal web surfing. But today, most mobile handheld devices have relatively poor web browsing capability because of the small bandwidth of wireless connection, the small speed of CPU, the small capacity of RAM and Flash ROM, the small display size of LCD and the short lifecycle of battery. Users have to endure bigger communication latency than Desk PC's one because of these factors. In this paper, we propose an effective pre-refresh mechanism for handheld device's embedded web browser so as to make user's web surfing faster. The experiment was done using the simulator designed by ourselves and the experiment result demonstrates the proposed mechanism has a good performance to make web surfing faster.

• 한국HCI학회:학술대회논문집
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• 2007.02b
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• pp.512-517
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• 2007

다양한 디지털 가전제품을 제조하는 회사들은 초기에 제품 하나하나에 제품의 사용경험을 담는데 비중을 높여 개발을 하였다. 하지만 제품이 알려지고 종류가 많아지면서 각 제품들을 아우르는 사용자 경험요소 통합화가 필요하게 되었다. 이에 다양한 화면 사이즈와 Input Device를 가진 Handheld Device들 간의 일관된 사용 경험(user experiences)을 제공하는 것을 목적으로 하는 연구가 진행되었다. 대상이 된 제품들은 Digital Media Broadcasting의 수신, Multimedia 파일이 재생, 파일 creation 등이 가능한 Handheld Devices였고, 각 제품들은 특정 기능에 충실한 UI를 구현하고 있다는 특징이 있다. 따라서, 기존 제품의 사용성을 저해하지 않는 수준의 표준화가 필요하며 기존 UI 사용성과 표준화 UI 사용성 간의 조화가 중요 하였다. 기존 제품의 개별 특징을 분석하고 Handheld Device의 사용자 요구사항을 조사를 통해 사용경험 요소를 발굴하고 Navigation, Menu Hierarchy, Screen Layout 등의 설계를 통해 Prototype 개발을 하고 Usability Test를 통해 보완을 하였다. Usability Test는 한국, 미국, 영국, 중국 4개국에서 광범위한 사용자 조사가 이루어졌다. 국가 선정은 제품의 주요 시장 및 각 대륙을 대표하는 기준으로 선정되었다. 사용자 그룹은 연령, 지식 수준, 성별에 구분되었고 Web Survey 1000명, Usability Test는 각 국가별 총 100명이 넘는 참석자에 의한 데이터 분석이 이루어 졌다. 이렇게 조사된 데이터를 바탕으로 UI 사용경험 요소를 정의하고 제품의 공통 가이드와 개별 가이드를 개발하는 일련의 프로세스를 확립하고 검증하였다. 본 논문을 통해 대상 제품들의 다양한 특성을 살리면서도 user Interface의 일관성 원칙을 설립하기 위해 시도했던 방법과 과정을 기술하고, 이 과정을 통해서 얻은 결과와 실제적인 경험을 소개한다.

• IE interfaces
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• v.22 no.4
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• pp.347-358
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• 2009

Panning tasks caused by both a small screen and the lower resolution of handheld devices are known to decrease the usability of a mobile internet service. To solve this problem, we proposed FTND, an improved version of Tap-N-Drag widely used in various mobile web browsers. 30 participants performed the panning tasks with FTND embedded in combinations of 2 panning directions of Push Background user interface and Push Viewpoint user interface and 5 panning ratios of 100% (a panning ratio of Tap- N-Drag), 300%, 500%, 700%, and 900%. The usability of FTND was assessed by an objective performance and a subjective preference. The objective performance was measured by a task completion time, the number of clicks, and the number of pixels. The subjective preference was measured by satisfaction, accuracy and ease of use. Push Viewpoint user interface at the panning ratios of 300%, 500%, and 700% proved to be the most efficient way for panning tasks with small handheld devices when performing the task by using the right hand thumb.

• IEIE Transactions on Smart Processing and Computing
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• v.1 no.2
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• pp.78-87
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• 2012

In this paper, we address the tracking problem caused by camera motion and rolling shutter effects associated with CMOS sensors in consumer handheld cameras, such as mobile cameras, digital cameras, and digital camcorders. A modified particle filtering method is proposed for simultaneously tracking objects and compensating for the effects of camera motion. The proposed method uses an elastic registration algorithm (ER) that considers the global affine motion as well as the brightness and contrast between images, assuming that camera motion results in an affine transform of the image between two successive frames. By assuming that the camera motion is modeled globally by an affine transform, only the global affine model instead of the local model was considered. Only the brightness parameter was used in intensity variation. The contrast parameters used in the original ER algorithm were ignored because the change in illumination is small enough between temporally adjacent frames. The proposed particle filtering consists of the following four steps: (i) prediction step, (ii) compensating prediction state error based on camera motion estimation, (iii) update step and (iv) re-sampling step. A larger number of particles are needed when camera motion generates a prediction state error of an object at the prediction step. The proposed method robustly tracks the object of interest by compensating for the prediction state error using the affine motion model estimated from ER. Experimental results show that the proposed method outperforms the conventional particle filter, and can track moving objects robustly in consumer handheld imaging devices.

• 한국HCI학회:학술대회논문집
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• 2007.02b
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• pp.153-158
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• 2007

기존의 모바일 기기들은 일반화된 고정 인터페이스 상태의 제품으로, 사용자가 단순 학습을 통해 반복된 인터렉션과 구성만을 이용하는 수준이었으나 최근과 같이 기기가 지능적이고 다양화되면서 개인의 요구와 특성을 반영한 인터페이스 방법들을 요구하기 시작하였다. 이에 따라 일반적 성향에 맞추어진 Universal UI와 개인의 특성에 맞춰진 Customizing UI의 양립적 이슈는 지속적으로 대치되어 왔다. 그러므로 이를 서로 적절한 수준에서 상호 보완하여 디자인하는 것은 그 형태나 속성을 떠나 최신 UI의 기본적인 필요충분조건이 되었다. Universal UI는 인식과 행동패턴을 달리하는 사람들의 공통분모를 찾아냄으로써 표준화의 Solution을 찾아낼 수 있었지만 Customizing에 대한 해답은 사용자 심리, 문화, 역사까지 고려해야 한다. 우리는 이 두 부분을 모두 만족하는 다방면의 멘탈모델 수립과 UT검증을 통해 모바일 기기에서 최적의 인터페이스 개발을 진행하게 되었다. 이러한 Customizing에 대한 연구는 기기 사용자의 지역과, 문화적 특성에 따라 최적화된 인터페이스를 제공할 수 있기에 기기 제조사는 Future work을 위해서라도 이러한 부분에의 충분한 연구 의의가 있다고 할 수 있다. 우리는 본 논문에서와 같은 Personalization과, 선호 기능을 좀 더 쉽게 적응하고 사용할 수 있도록 하는 Customization 을 통해 사용자의 성향을 적극 반영할 수 있는 모바일 인터페이스 제품 개발로 한 단계 발전시켰다고 본다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.2
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• pp.404-420
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• 2021

In this paper, an automatic system of locating the indoor area with weak or no mobile signal was proposed and demonstrated experimentally by using the Internet of Things (IoT) technology. Nowadays, the technicians of mobile services providers need to go along with numerous heavy equipment to measure and record the mobile signal strength at outside environment. Recently, there are systems proposed to do such measurement at outdoor area by using the IoT technology automatically. However, these works could not be applied in the indoor area since there are difficulties to do the indoor mapping and positioning. In this work, the Bluetooth Low Energy (BLE) was used to tackle these two difficulties. After a proper placement of BLE in the testing site, while the technician walk around with a handheld analyzer, the data can be obtained accordingly for further analysis in the proposed system which includes the construction of floor plan, detection of mobile signal strength and suggestion of indoor base stations. The gift wrapping and centroid algorithms were used during the analysis. The experimental results showed that the proposed system successfully demonstrated the indoor mapping, positioning of weak mobile signal area and suggestion of indoor base stations for the normal rectangular rooms with an area of 100 m² on single floor.

• Proceedings of the Korea Contents Association Conference
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• 2017.05a
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• pp.401-402
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• 2017

Advances in the Internet and network technology and the rapidly growing number of personal devices result in the fast growth of E-Commerce, M-Commerce. Nowadays, location-based services are widely used in E-commerce. A location-based service (LBS) is a service based on the geographical positions of mobile handheld devices such as smart phones or tablet computers. In this paper I will view the combination of the E-commerce and LBS.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.4
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• pp.569-577
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• 2009

Mobile information retrieval is an evolving branch of information retrieval that is centered on mobile and ubiquitous environments. In general, mobile devices are characterized by lightweight, low power, small memory, small display, limited input/output, low bandwidth, and so on. Some of these characteristics make it impossible to apply general information retrieval to mobile environments without any modification. In order to relieve this problem, we design and implement an information retrieval system for mobile devices like wireless phones, PDA and handheld devices. We use document summarization techniques to alleviate the limitation of small display and user profiles to retrieve the most proper documents for each individual user for personalized search. Futhermore we use meta-search to lighten some burdens visiting several portal sites. In this paper, we have implemented and demonstrated the proposed mobile information retrieval system on the domain of travel and received good evaluation from users subjectively.