• Journal of the Korean institute of surface engineering
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• v.56 no.4
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• pp.273-282
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• 2023

In this study, the surface of Polyetheretherketone (PEEK) disks was modified to have a hydrophilic surface by applying a coating of Polyethylene glycol (PEG), Hyaluronic acid(HA), and Poly-Dopamine(PDA). The investigation aimed to examine whether the coated surfaces showed enhanced bioactivity for orthopedic applications compared to the pure PEEK. The microstructure, surface characteristics, and wettability of PEEK coated with PEG, HA, and PDA were analyzed using scanning electron microscopy(SEM), FT-IR spectrophotometer, Roughness Measurement System, Micro-Vickers, and Contact angle measurement. The mechanical properties were analyzed using a tensile testing machine, while the MTT assay for cell activity was analyzed using a microplate reader to measure optical density. According to the SEM and FT-IR results, the composition and crystal structure of PEG, HA and PDA coated surface were verified. Also, roughness, hardness, and contact angle were all improved in the coating group compared to the pure PEEK. We checked the HepG2 cell proliferation by using MTT assay on 7th days. In MTT assay results, HepG2 cell proliferation was increased with time, at 7 days, cell viability on discs coated with PDA was significantly higher than pure PEEK, PEG, HA coated group. PDA coated PEEK exhibited the highest surface roughness, hardness, contact angle, and cell activity. The mechanical properties were not affected by the presence of the coating.

• MALSORI
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• no.43
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• pp.57-72
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• 2002

The technology of speech recognition has a wide field of application. The range of such technology is spreading into mobile computing having the large amount of movement for communication equipments at the present time. Particularly, recognition in internet environment is rapidly moving into mobile environment. Because of these environments, users want the faster speed of data transmission and the lighter portable equipment for data access. That is PDA(Personal Digital Assistant). Therefore, we designed a triphone-based text independent vocabulary recognizer for the implementation of speech control in this paper. The text independent vocabulary recognizer is based on the state .joint algorithm with decision trees

• Knowledge Management Research
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• v.6 no.1
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• pp.71-84
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• 2005

This paper is aimed at investigating the influence of the fit between PDA (Personal Digital Assistant) driven mobile technology and tasks on performance. Our research motive was adopted from the burgeoning mobile technology which can be easily observed in modem management. Fit theory has been widely applied to proved the relationship between technology and tasks. However, there are few studies about the fit between mobile technology and tasks. A the advent of the IT, mobile technology started to affect individuals' lifestyle as well as the management style of firms. For the purpose of proving those hypotheses, we collected 173 questionnaires from 20 firms such as manufacturing industry, financial business, service company, telecommunication company which deem using the PDA technology for their management. We applied factor analysis and path analysis for our experiments Results revealed that the mobile technology holds a statistically significant fit with tasks and Individual characteristics.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.42 no.1
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• pp.53-60
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• 2005

In this paper, we developed a mobile fingerprint identification system using wireless LAN based on IEEE 802.11 or mobile networks based on CDMA. The proposed system contains a server system to register fingerprints and ID data, clients system which is PDA with WLAN or CDMA module and fingerprint identification module.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2008.04a
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• pp.396-399
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• 2008

Kalman Filter is an efficient recursive filter that estimates the state of a dynamic system from a series of incomplete and noisy measurement. The filter is very powerful in the field of autonomous and assisted navigation. In this paper, we carry out comparative stduy to validate the performance of the application of Kalman Filter. We will build personal localization system based on Cricket mote, our system can present the real-time position of person when the man with PDA moves around. The proposed system is composed of cricket sensor networks, PDA and host computer. There is one listener attached to the PDA. The PDA will get the distance data from the listener synchronously. It will calculate the position of the person in the coordinate of the Cricket system with the trilateration method. Furthermore, it sends the real-time position information to the host computer by Bluetooth. The host computer will use Kalman Filter to process data and get the final estimated track of the person.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2001.06a
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• pp.281-284
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• 2001

In this paper, we present a car number retrieving system using speech recogntion and speech synthesis for PDA. This system consist of 4-digit numbers and command speech recognition as well its speech synthesis. Experiment results showed 4-digit numbers recognition rate 97% and commands recognition 99% through speaker-independent method.

• Journal of Sensor Science and Technology
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• v.13 no.6
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• pp.446-453
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• 2004

A portable electronic tongue (E-Tongue) system using an array of ion-selective electrode (ISE) and personal digital assistants (PDA) for recognizing and analyzing food and drink have been designed. By the employment of PDA, the complex algorithm such as fuzzy c-means algorithm (FCMA) could be used in E-Tongue, PUMA could iteratively solve the cluster centers of pre-determined standard patterns. And the membership between the standard patterns and unknown pattern could be analyzed easily by the present E-Tongue combined with PDA.

• The Journal of the Korea Contents Association
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• v.6 no.5
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• pp.14-19
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• 2006

In this paper, we describe an arrival time guidance system of circular vehicles using GPS, CDMA and TCP/IP technology. The on-board equipment consists of a GPS receiver and a PDA phone. The on-board equipment sends the current position data of the vehicle to the positioning server via CDMA and Internet. The server predicts the arrival time to the next bus-stop. Any user can lookup the current position and the predicted arrival time of the vehicle utilizing his mobile phone, PDA phone, or Web.

• Journal of ILASS-Korea
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• v.10 no.2
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• pp.32-40
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• 2005

This paper presents the analytical approaches to predict cutting fluid aerosol formation characteristics in machining process. The prediction model which is based on the rotary atomization theory analyzes aerosol behaviors in terms of size and concentration. Experiments were tarried out to verify the aerosol formation prediction model under various operational conditions. The experimental results which are obtained by Dual-PDA measurement show resonable agreement with prediction results of aerosol concentration. This study can be provided as a basis to estimate and control the hazardous cutting fluid aerosol in machining process in view of environmental consciousness.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10c
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• pp.436-438
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• 2002

본 논문에서는 PDA(Personal Digital Assistants)을 이용하여 보안성 있는 흠 네트워크 가전 단말기 제어 시스템을 개발한다. PDA와 같은 이동 단말기가 발달함에 따라 외부 네트워크에서 흠 네트워크에 접속하여 가전 장비들을 제어하는 연구가 매우 중요하다. 그러나 방화벽만으로 홈 네트워크의 장비를 안전하게 제어하기에는 많은 문제점을 지니고 있다. 본 논문에서는 외부네트워크에서 흠 네트워크로의 안전한 접근 및 제어를 위한 가상 사설망(Virtual Private Network)을 흠 네트워크 제어 시스템에 적용하는 방법을 제시한다. 또한 다양한 흠 네트워크 단말기에 적용 할 수 있고 홈 네트워크간의 호환성을 높이기 위해서 OSGi(Open Service Gateway Initiative)프레임워크를 사용한다.