• Proceedings of the IEEK Conference
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• 2002.06c
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• pp.5-8
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• 2002

In this paper, we propose the self-autonomous algorithm for mobile robot system. The proposed mobile robot system controlled by Personal Digital Assistant(PDA) can follow the target at regular intervals. The mobile robot can evaluate the distance between robot and target with ultrasonic sensors, transmits the distance to the PDA. The velocity and direction decided in PDA are transmitted to the mobile robot with wireless LAN communication. Considering the state, velocity-changing and distance-maintenance, of the mobile robot, driving velocity and direction are applied. For safety, the velocity of the mobile robot is changed step by step. As a result, we confirm the ability of following the target with proposed mobile robot.

• Journal of the Institute of Convergence Signal Processing
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• v.10 no.3
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• pp.170-175
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• 2009

In this paper, we propose real time automatic speaker verification (ASV) system to protect personal information on personal digital assistant (PDA) device. Recently, the capacity of PDA has extended and been popular, especially for mobile environment such as mobile commerce (M-commerce). However, there still exist lots of difficulties for practical application of ASV utility to PDA device because it requires too much computational complexity. To solve this problem, we apply the method to relieve the computational burden by performing the preprocessing such as spectral subtraction and speech detection during the speech utterance. Also by applying the hidden Markov model (HMM) optimal state alignment and the sequential probability ratio test (SPRT), we can get much faster processing results. The whole system implementation is simple and compact enough to fit well with PDA device's limited memory and low CPU speed.

• Journal of Korea Multimedia Society
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• v.8 no.10
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• pp.1383-1390
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• 2005

Mobile Multimedia Storage Server should provide to store and transfer a data that the number of concurrent datum by Personal Digital Assistant(PDA) requests in real time. simultaneously. But, While the large number of a PDA request connect to MTS (Mobile Translation Storage) server with BottleNeck problem in mobile internet environment by many constraints such as limited bandwidth can be introduced. This paper introduces an optimal method of new DVDS (Dynamic Variable Disk Scheduling) for MTS server which is based on the Weight Value to solve the BottleNeck problems that occur when transfer and store capture images through mounted digital camera on the PDA in real time simultaneously. The comparison with previous research shows that the proposed scheme provides better.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04b
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• pp.451-453
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• 2001

제스쳐(gesture)는 마우스 또는 스타일러스의 난일 표시(single mark)를 이용하여 객체들과 기능들을 식별하는 문서 편집 도구의 강력한 방법들 주 하나이다. 마우스를 위한 제스쳐는 주로 데스크 팁 기반의 환경을 위해 개발되어지고 스타일러스를 위한 제스쳐는 보통 휴대용 컴퓨터를 위해 개발되어진다[2]. 현대는 PDA(Personal Digital Assistant)시스템의 스타일러스를 위한 제스쳐 개발이 활발하게 이루어지고 있다.[3]. 하지만 PDA 시스템에서는 인식에 의한 문자 입력의 보조 도구 정도의 수준에서 제스쳐가 사용되어진다. 본 논문에서는 PDA 시스템에서 사용되는 키보드의 키 역할을 하는 기존의 제스쳐와는 달리 사용자 입력과 제스쳐에 차별을 두지 않고 한 화면에서 직접적이 제스쳐가 가능한 환경을 개발하고 다양한 제스쳐 인식 방법을 제안한다. PDA 시스템에서의 제약을 최소화하기 위해 펜 기반의 입력에서 각 스트록을 간략화시켜 정보를 최소호 한 뒤 각 스트록을 양방향 연결 리스트를 이용해 연결하였다. 제스쳐(gesture)는 삽입, 삭제의 기본적인 것들을 비롯하여 이동, 복사, 붙임과 같은 제스쳐도 포함되어 있다. 제스쳐(gesture)의 인식은 각 스트록의 바운딩 박스와 점들의 위치 정보, 스트록 생성 순서에 기반하여 이루어지기 때문에, 이로 인해 펜 기반의문서 에디터 사용에서 요구되는 다른 제약 없이 오로지 펜만으로 모두 편집 환경을 구현할 수 있다.

• Journal of Korea Multimedia Society
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• v.11 no.10
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• pp.1376-1384
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• 2008

Numerous researches on network self-configuration have been conducted on Wireless Sensor Network (WSN) and Ad Hoc network but the results have not been applied yet for factory automation. This paper presents development of intelligent process management systems conducting process monitoring and control irrelevant to physical position of a plant operator. The systems are indispensable for diagnosis of rotating machines which cannot exploit wired network. The system was implemented in a Personal Digital Assistant (PDA) using Bluetooth communication protocol. When a mobile terminal reaches to communication range of the process management server, the server detects the mobile terminal to reconfigure plant network automatically. The server authenticates a user of the terminal to download and installs monitoring and control program considering authorized level of the user. If the terminal leaves communication range of the server, it deletes the node from the network and removes the program automatically to save resources and prevent security problems such as missing terminal. Operation of developed functions was verified in a testbed emulating steel-making plant.

• Archives of design research
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• v.15 no.3
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• pp.249-258
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• 2002

This study is about the effect on the user's cognitive stress by font size when they read on PDA(Personal Digital Assistant). The evaluation was done through both subjective evaluation and physiological one, which is brain wave test, while the research and analysis were focused on the relationship between the user's cognitive stress and font size. The two final results were found out as follows. 1) Font sizes, which were tested, were 8, 10, 12, 14, and 16 points. Among theses, font size 14 was the least stressful for the users, while the most stressful size was found out 8 points. 2) The cerebral cortex reaction according to the font size activated occipital lobe, parietal lobe of occipital visual area. Here we could come to a very Important conclusion that the smaller font size on mobile information appliances made users the more stressed.

• The Journal of Engineering Research
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• v.7 no.1
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• pp.61-70
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• 2005

Conventional geological survey utilizes the manual compass for mass amount of measurements of the geologic structure. Portable multifunction digital compass system was required by more detailed geological survey, due to increasing construction for rock slopes and runnels. In this paper, the system was implemented by using Intel PXA 255 embedded board as a system controller, and was composed of tilting sensor, digital azimuth sensor, and Global Positioning System (GPS) module. After the measured location, strike, and the angle of dip with our implemented system were transmitted to Personal Digital Assistant (PDA) or notebook, these data could be used for geologic structure analysis. It is expected that the availability of cheap and improved digital compass will reduce the coast and time of geological survey extensively.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.634-637
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• 2007

Self management of chronic asthma is of great importance, since the disease could lead the patient into an emergent situation. In the present study, we describe implementation of a personal digital assistant(PDA) based asthma management system for personal application including symptom and medication to prevent from the potential exacerbation of the disease. The software program was written by the Visual C++ tool in the mobile computing environment and Object Store was applied for data management. User friendly GUI environment was provided for the patient to input his/her daily condition and self treatment such as medication for successful management. The input screen design substituted for keyboard input to a mouse in order to easy to select an item and minimize the keyboard input. The implementation results of this system., Real-time data collection and process were possible and be able to have been carried effectively out a continuous symptom, a medication of asthma patients, risk management.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.11a
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• pp.315-318
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• 2004

모바일 통신 환경이 발전하고 보편화되면서 사용자들은 휴대폰뿐만 아니라 PDA(Personal Digital Assistant)를 통해 다양한 컨텐츠 서비스를 받고 있다. 그러나 낮은 대역폭, 높은 네트워크 지연, 자주 끊기는 네트워크 환경으로 인해 모바일 환경에서의 서비스가 원활히 되지 않는다. 이를 해결하기 위해 정보가 있는 장소로 이동함으로 중간 단계의 데이터들이 네트워크를 통과하여 자원을 소모하는 것을 막고, 네트워크의 대역폭을 보존하고 지연을 줄이고 네트워크가 자주 끊어지더라도 계속해서 정보를 찾고 사용자와 반응할 수 있도록 모바일 에이전트 기술을 적용한다. 본 논문에서는 PDA 서비스를 위한 모바일 에이전트 개발을 위한 컴퓨팅 아키텍처를 정의하고 개발을 용이하기 위한 재사용성 및 이식성을 위해 컴포넌트를 기반으로 한다. 구현 관점에서 모바일 에이전트의 기능은 컴포넌트를 기반하며, 모바일 에이전트 아키텍처를 4개의 계층으로 정의하고, PDA 서비스를 위한 사례를 제시 한다. 이를 통해 모바일 환경에서 사용자의 자료접근을 용이하게 하며 컴포넌트를 통한 개발의 효율성을 기대할 수 있다.

• Journal of Korea Multimedia Society
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• v.7 no.12
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• pp.1754-1764
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• 2004

Lately mobile handheld devices such as Personal Digital Assistant (PDA) and cellular phones are getting more popular for personal web surfing. However, today most mobile handheld devices have relatively poor web browsing capability due to their low performance so their users have to suffer longer communication latency than those of desktop Personal Computers (PCs). In this paper, we propose an effective pre-refresh mechanism for embedded web browser of mobile handheld devices to reduce this problem. The proposed mechanism uses the idle time to pre-refresh the expired web objects in an embedded web browser's cache memory. It increases the utilization of Central Processing Unit (CPU) power and network bandwidth during the idle time and consequently reduces the client's latency and web browsing cost. An experiment was done using a simulator designed by us to evaluate the efficacy of the proposed mechanism. The experiment result demonstrates that it has a good performance to make web surfing faster.