• Journal of Information Technology Services
• /
• v.8 no.1
• /
• pp.179-192
• /
• 2009

In wireless environments, it is very effective to introduce a data broadcast system for providing a number of clients with mobile data services. In particular, an efficient broadcast scheduling and a caching strategy are very important for performance of data broadcast systems in wireless environments which have such inherent restrictions as low bandwidth, frequent disconnections, and short battery life. In this paper, we present a data broadcast scheduling strategy using bit vectors to cope with dynamic request patterns of clients. In addition, we also propose an efficient caching strategy, 2FWT, that takes characteristics of the broadcast scheduling strategy into account. Finally, we evaluate performance of the data broadcast system. According to the results, the proposed system generally shows better performance than others.

• The Journal of Korean Physical Therapy
• /
• v.26 no.6
• /
• pp.398-402
• /
• 2014

Purpose: This study was carried out in order to verify actual applicability of mental practice in the clinical field by applying it to Parkinson disease patients. Methods: : The number of subjects was three and they were aged between 65 and 69. One year or longer period has passed since they were diagnosed with Parkinson disease. The baseline A consisted of three sessions. After the baseline period, the researcher applied mental practice to the subjects once per day, for 20 minutes per each time, for 10 sessions. The no-intervention withdrawal phase was composed of three sessions. Outcome measures 10 meter walking test(10MWT), timed up and go (TUG) test, 8-figure walk test (8FWT). Results: All results indicated that 10 MWT, TUG, F8WT was improved when compared mental practice(B) to pre base line(A). base line(A) after mental practice intervention(B) was also sustained. Conclusion: As a result of the mental practice, we can know that it helps straight gait, dynamic balance, curved gait to improve.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.15 no.6
• /
• pp.73-81
• /
• 2001

This study uses the distributed parameter systems resented by the spatial discretization technique. In this paper, the distributed parameter systems are converted into lumped parameter systems, End fast Walsh transform and the Picard's iteration method are allied to analysis the state of the systems. This thesis presents a new algorithm which usefully exercises the optimal contro1 in the distributed parameter systems. In exercising the optimal control of the distributed parameter systems, the excellent consequences are found without using the existing decentralized contro1 or hierarchical control method. This study can be applied to the linear time-varying systems and the non-linear systems. Farther researches are required to solve the problems of convergence in case of the numerous applicable intervals. The simulation proves the effectiveness of the proposed algorithm.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.10 no.4
• /
• pp.13-19
• /
• 2000

With the rapid development of the information communication technology, more and more distribution multimedia data and electronic publishing in the web, has created a need for the copyright protection with authentication of digital information. In this paper, we propose a multi-watermarking adding and adaptive spectral watermark algorithm well adaptive frequency domain of each hierarchical using orthogonal forward wavelet transform(FWT. Numerical test results, created watermarking image robustness not only image transform such as low-pass filtering, bluring, sharpen filtering, wavelet compression but also brightness, contrast gamma correction, histogram equalization, cropping.

• The Korean Journal of Ecology
• /
• v.17 no.2
• /
• pp.131-141
• /
• 1994

One-year-old yellow-poplar (Liriodendron tulipifera L.) and sweetgum (Liquidambar styraciflua L.) seedlings were exposed to 0.10 ${\mu}l/l\;O_3$and simulated acid rain at pH 3.0 for ten consecutive weeks. Shoot height growth (SHG), fresh weight (FWT), dry weight (DWT), apparent plastochron duration (APD) and foliar nutrient concentrations were measured. None of growth measurements, except the apparent plastochron duration (APD), were significantly affected by any treatment in yellow-poplar seedlings. APD was approximately 30% higher in seedlings exposed to $0.1{\mu}l/l\;O_3$ ＋ pH 5.6 solution than any other treatment. Ozone significantly reduced SHG of sweetgum seedlings by 24% at the end of the ten-week fumigation. There were also significant effects of single and combined effects of ozone and simulated acid rain on APD in sweetgum. APD was significantly increased by 19.8% and 25.7% in seedlings exposed to $0.1{\mu}l/l\;O_3$ and pH 5.6 solution, respectively, and resulted in 46.1% higher APD in seedlings exposed to $0.1{\mu}l/l\;O_3$ + pH 5.6 solution compared with seedlings exposed to $0.0{\mu}l/l\;O_3$ ＋ pH 3.0 solution. Phosphorus and sulphur were significantly greater in seedlings exposed to simulated rain at pH 3.0 compared with pH 5.6 for both species. Foliar S concentration was higher in seedlings exposed to $0.0{\mu}l/l\;O_3$ ＋ pH 3.0 than in seedlings exposed to any other treatment in sweetgum. Ozone significantly increased Ca in sweetgum seedlings, however, ozone reduced Ca in yellow-poplar. Ozone also reduced S and Mg in sweetgum seedlings.