• Journal of Internet Computing and Services
• /
• v.11 no.3
• /
• pp.131-137
• /
• 2010

Today, many museums are changing their forms with ubiquitous environment. Unlike traditional museums providing only static text-based information attached to its corresponding artifacts to visitors, those ubiquitous museums provide not only artifacts' text information, but also many different forms of information such as sound or media through personal digital assistance or cell phones. However, these existing ubiquitous museums still provide each visitor only with artifact-centric information in very simple ways. Also this disadvantageous feature causes high gallery congestion problem resulting from providing a uniform path for every visitor. These limitations may be the biggest barrier to providing more various and useful information about artifacts to visitors through considering each visitor's preference. This paper propose a new optimal viewing path search algorithm to provide comfortable museum viewing for each visitor according to its preference. Also, a new congestion control method is developed to protect visitors from being put in some hot spots on their museum viewing, improving its comfort to a maximum.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.6 no.8
• /
• pp.1223-1233
• /
• 2002

Recently various electronic books (I-Book) based on PDA (personal digital assistance) that we can easily use anytime and anywhere have been developed. Volume and weight of the E-Book is much less than that of traditional books. In that reason, it is easy to carry and serve us with contents by diverse functions such as searching, bookmark, dictionary, and playing of color image, sound or moving picture. On account of these advantages, many products connected with I-Book have been emerged in the market. However a product connected with educational contents is scarce, because it requires not only normal function but also additional functions such as a problem solving. Therefore it is actually necessary to develop a browser and an editor for educational contents. In this paper, we express educational contents by XML and define structure of document with XML schema. Then, we design and implement an editor and a browser that can manage educational contents on PDA.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.8 no.3
• /
• pp.541-548
• /
• 2007

The workflow, one of core features for modern business operation, models common elements and their relationships in business processes. The research is focused on how to adapt the workflow model to the healthcare examination which becomes popular these days. Especially, we intend to have fully automated process for healthcare examination by providing customers with PDA with RFTD chip. In order to realize this goal, this paper proposes the design of software architectures the class structures, and the definition of messages used for the system interactions. In other word, the paper shows the analysis of healthcare application in terms of service scenario and the design of workflow engine ant ubiquitous healthcare application under the Object-Oriented programming environment. the The result of the study may also enable the unmanned healthcare examination as well as ubiquitous based healcare examination sooner or later.

• Journal of Biomedical Engineering Research
• /
• v.27 no.5
• /
• pp.274-281
• /
• 2006

In this paper, we propose a ubiquitous $SaO_2$ monitoring system for patients using oxygen therapy. For these patients, the ability to monitor oxygen saturation ubiquitously is very important fur accurate adjustment of ventilator's flow rate to match the patient's time-varying requirements with the shortest lag time possible. We have developed a portable device to measure $SaO_2$ and transmit it to hospital in real-time or in store-and-forward mode through the integration of $Bluetooth^{TM}$ technology and the code division multiple access (CDMA) cellular network. We also developed software for doctors to receive and manage the patients' $SaO_2$ information. Performance of the developed system was evaluated as acceptable by assessing the accuracy of the measured oxygen saturation value and the stability of communication network. Test results in real clinical setting demonstrate that our system is feasible for immediate use in home oxygen therapy.

• Journal of the Korean Society of Industry Convergence
• /
• v.21 no.6
• /
• pp.265-271
• /
• 2018

DC-DC buck converter is a critical building block in the power management integrated circuit (PMIC) architecture for the portable devices such as cellular phone, personal digital assistance (PDA) because of its power efficiency over a wide range of conversion ratio. To ensure a safe operation, avoid unexpected damages and enhance the reliability of the converter, fully-integrated protection circuits such as over voltage protection (OVP), under voltage lock out (UVLO), startup, and thermal shutdown (TSD) blocks are designed. In this paper, these three fully-integrated protection circuit blocks are proposed for use in the DC-DC buck converter. The buck converter with proposed protection blocks is operated with a switching frequency of 1 MHz in continuous conduction mode (CCM). In order to verify the proposed scheme, the buck converter has been designed using a 180 nm CMOS technology. The UVLO circuit is designed to track the input voltage and turns on/off the buck converter when the input voltage is higher/lower than 2.6 V, respectively. The OVP circuit blocks the buck converter's operation when the input voltage is over 3.3 V, thereby preventing the destruction of the devices inside the controller IC. The TSD circuit shuts down the converter's operation when the temperature is over $85^{\circ}C$. In order to verify the proposed scheme, these protection circuits were firstly verified through the simulation in SPICE. The proposed protection circuits were then fabricated and the measured results showed a good matching with the simulation results.

• Journal of Sensor Science and Technology
• /
• v.14 no.2
• /
• pp.69-77
• /
• 2005

The electronic nose (e-nose) has been used in food industry and quality controls in plastic packaging. Recently it finds its applications in medical diagnosis, specifically on detection of diabetes, pulmonary or gastrointestinal problem, or infections by examining odors in the breath or tissues with its odor characterizing ability. Moreover, the use of portable e-nose enables the on-site measurements and analysis of vapors without extra gas-sampling units. This is expected to widen the application of the e-nose in various fields including point-of-care-test or e-health. In this study, a PDA-based portable e-nose was developed using micro-machined gas sensor array and miniaturized electronic interfaces. The rich capacities of the PDA in its computing power and various interfaces are expected to provide the rapid and application specific development of the diagnostic devices, and easy connection to other facilities through information technology (IT) infra. For performance verification of the developed portable e-nose system, Six different vapors were measured using the system. Seven different carbon-black polymer composites were used for the sensor array. The results showed the reproducibility of the measured data and the distinguishable patterns between the vapor species. Additionally, the application of two typical pattern recognition algorithms verified the possibility of the automatic vapor recognition from the portable measurements. These validated the portable e-nose based on PDA developed in this study.