• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.385-387
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• 2005

In this study, we tried to implement a PDA (Personal Digital Assistant)-based audiometric system to test hearing disorder. Due to the inherent handy nature of PDA system, our hearing test system can be easily performed in a local environment and consequently the measured audiometric data are stored and queryed via a built-in a PDA database system.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.1
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• pp.42-44
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• 2006

In this paper, we tried to implement a PDA (Personal Digital Assistant)-based audiometric system to test hearing disorder. Due to the inherent handy nature of PDA system, our hearing test system can be easily performed in an user's local environment and consequently the measured audiometric data can be stored and queryed locally via a built-in PDA database system.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.334-341
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• 2002

Nowadays, owing to the development of analysis techniques for PDA test, we can evaluate the serious damage of pile during driving in site. In this study, we checked the damage of pile by pulling it out after evaluation of the pile damage during driving by PDA testing. After that, almost damaged pile was checked and the outline depth of damage could be verified. To increase the quality of driven pile, we have to increase the number of PDA testing for drivability analysis with checking the damage especially for preliminary pile driving and dynamic load test for checking the bearing capacity and consider the application of driving by energy monitoring.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.3
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• pp.34-41
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• 2009

Recently, information-Ievel of the people has been increased with growing IT cutting-edge technology. There is a trend to combine these achievements with information-technology, ubiquitous technology, and mobile technology in the field of transportation. Along with this trend, a PDA-based traffic accident investigation device was developed. This paper established the evaluation method of feasibility test on the PDA device, and performed qualitative and quantitative evaluation as compared with the current practice (manual investigation). Test results showed that traffic accident investigation using the PDA device was faster and more convenient than manual investigation. It is expected that the reliability of accident investigation will be improved by applying this tool with minor modifications.

• 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 the Korean Wood Science and Technology
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• v.42 no.1
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• pp.41-48
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• 2014

To development of the low toxic preservatives, we prepared 29 kinds of chemicals using dinotefuran of low toxic insecticide, IPBC and propiconazol of fungicide, and clove oil has fungicidal activity, but is harmless to humans. It was conducted to investigate the inhibitory effectiveness of mycelial growth and anti-mold effectiveness to treated PDA medium and wood specimen with prepared chemicals. It was not showed anti-mold effectiveness that solvent and emulsifier form preservatives. Therefor, we thought that only four component, dinotefuran, IPBC, propiconazol and clove oil, has anti-mold effectiveness. In the PDA medium test, the preservative which has much IPBC showed high anti-mold effectiveness. By the wood specimen test, it was known that many prepared preservatives which showed good inhibitory effectiveness of mycelial growth in the PDA medium test, have not anti-mold effectiveness. Of all prepared preservatives in this study, only three preservatives containing dinotefuran and IPBC, or adding clove oil appeared the excellent anti-mold effectiveness.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1259-1268
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• 2006

Dynamic pile loading test using PDA was introduced in 1994. Because of its economy and relatively easy and simple procedure, the number of PDA application increased quite rapidly. It is assumed that more than 10,000 dynamic pile loading tests are done annually. While the number of testing increases sharply, the quality of the tests does not really improve but the number of serious problems due to improper testing increases. According to the limited experiences of the authors, the common problems found in most of the cases are caused by ignorance of the most basic and fundamental requirements. In this paper some case histories are explained and the proposed solution is introduced.

• Journal of the Korean Geotechnical Society
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• v.34 no.12
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• pp.115-131
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• 2018

Extension plate attached PHC piles and bolts spliced PHC piles were installed in field test site. Pile integrities were checked during installation with dynamic pile test and the actual pile conditions after installation were compared with integrity index (${\beta}$ index) by PDA test. Theoretically the break in near pile end or pile end (especially extension plate itself) was very difficult to access by integrity index (${\beta}$ index) and also require a high level of knowledge and field experience on PDA test. First actual wave equation of bolts spliced PHC piles due to bolts spliced equipment can be different with welding spliced. Second wave length of the stress wave from installing can be longer than the height of bolts spliced equipment (about 100 mm). Third Beta processing in PDA analysis function is very difficult to access without a high level of knowledge and field experience on wave equation. Above-mentioned three reasons can make conclusion that traditional PDA test in domestic site can not access the integrity of bolts spliced equipment in bolts spliced PHC piles.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.11-19
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• 2004

When pile foundation constructed by driving method, it is desirable to perform monitoring and estimation of pile drivability and bearing capacity using some suitable tools. Dynamic Pile Monitoring yields information regarding the hammer, driving system, and pile and soil behaviour that can be used to confirm the assumptions of wave equation analysis. Dynamic Pile Monitoring is performed with the Pile Driving Analyser. The Pile Driving Analyser (PDA) uses wave propagation theory to compute numerous variables that fully describe the condition of the hammer-pile-soil system in real time, following each hammer impact. This approach allows immediate field verification of hammer performance, driving efficiency, and an estimate of pile capacity. The PDA has been used widely as a most effective control method of pile installations. A set of PDA test was performed at the site of Donghea-1 Gas Platform Jacket which is located east of Ulsan. The drilling core sediments of location of jacket subsoil are composed of mud and sand, silt. In this case study, the results of PDA test which was applied to measurement and estimation of large diameter open ended steel pipe pile driven by underwater hydraulic hammer, MHU-800S, at the marine sediments were summarized.

• Journal of Information Processing Systems
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• v.2 no.2
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• pp.76-81
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• 2006

A PDA is used mainly for downloading data from a stationary server such as a desktop PC in an infrastructure network based on wireless LAN. Thus, the overall performance depends heavily on the performance of such downloading with PDA. Unfortunately, for a PDA the time taken to receive data from a PC is longer than the time taken to send it by 53%. Thus, we measured and analyzed all possible factors that could cause the receiving time of a PDA to be delayed with a test bed system. There are crucial factors: the TCP window size, file access time of a PDA, and the inter-packet delay that affects the receiving time of a PDA. The window size of a PDA during the downstream is reduced dramatically to 686 bytes from 32,581 bytes. In addition, because flash memory is embedded into a PDA, writing data into the flash memory takes twice as long as reading the data from it. To alleviate these, we propose three distinct remedies: First, in order to keep the window size at a sender constant, both the size of a socket send buffer for a desktop PC and the size of a socket receive buffer for a PDA should be increased. Second, to shorten its internal file access time, the size of an application buffer implemented in an application should be doubled. Finally, the inter-packet delay of a PDA and a desktop PC at the application layer should be adjusted asymmetrically to lower the traffic bottleneck between these heterogeneous terminals.